How to Edit a Photo in GIMP (10 Steps)

GIMP is first and foremost a photo editor – it can do many things beyond simple photo editing, but it was built to help everyday people get the best out of their photography. That’s why in this tutorial I’ve decided to show you a simple photo editing process for beginners. It starts with opening a photo and ends with exporting it to whatever filetype you want.

Since everyone has different tastes when it comes to the settings of your tools, I won’t get too much into which exact values you should use for each tool discussed here, but I’ll provide some general insight into why you use a tool and how to use it.

In the end, you’ll be able to create photo edits you enjoy and that look professional! The longer you work on crafting your style and understanding how GIMP’s tools work, the better you’ll get at this. Let’s dive in!

Step 1: Open Your Image

You’ll want to start by opening your photo into GIMP. The most common filetype used in GIMP is the JPEG – so I recommend using that (especially if it is coming straight from your camera).

To open your photo, go to File>Open (shown in the image above).

This will bring up your “Open Image” dialogue, which you can use to browse your computer for the location of the image you’d like to edit. Use the “Places” section (highlighted in green in the image above) to select from any hard drive from your computer, including external hard drives. Once you select a hard drive, you can then double click on folders to enter those folders until you have located your image.

In my case, I went to my E: drive, then navigated to the “Photography” folder, and finally the “Photo Editing Tutorial Article” folder.

Here, I can click on the JPEG image I want to open (red arrow in the image above). Clicking the file will bring up a preview of the image on the right-hand side of the Open Image dialogue. I’ll click the “Open” button to open the image into GIMP.

Step 2: Adjust the Levels

The first photo editing tool I like to use is the Levels tool. This tool allows you to adjust both the brightness/contrast of your image and the colors of your image. It’s also a pretty easy tool to use.

Before I access the Levels tool, I’ll duplicate my main photo layer in the layers panel. This keeps an original copy of the photo while we work. To duplicate the photo, click on the photo layer in the Layers dialogue to make it your active layer. Then, click the “Duplicate” icon (red arrow in the photo above) at the bottom.

I can then double-click on the layer name for this duplicate layer we created to rename it (green arrow). I’ll rename it “Edited” since we will be making our edits on this layer.

Now, with the Edited layer selected as my active layer (red arrow in the image above), I’ll go to Colors>Levels (green arrow). This will bring up a dialogue labeled “Adjust Color Levels.”

Value Channel

By default, the levels tool start on the “Value” channel (red arrow in the above photo), which allows you to adjust the brightness of your image as well as add some contrast.

Under the section titled “Input Levels” (outlined in green in the photo) you’ll see a histogram (blue arrow), as well as a gradient below the histogram (yellow arrow) that transitions from black to white, and finally a set of three triangles (black, gray, and white – from left to right – just below the gradient). Input Levels is a fancy term for the original values of your image prior to making any adjustments. So, the histogram that displays under “Input Values” shows you what your original image looks like in the form of a bar graph based on shadows, highlights, and mid-tones. The taller the bars in your histogram, the more there are of that value of pixel.

For example, this histogram has some very tall bars clustered on the left side of the histogram. This tells me that this image has a lot of darker pixels. On the far-right side of the histogram, on the other hand, there are very short bars. This tells me there are not many bright pixels in the image. So, to translate, this is a darker image overall.

The black triangle (red arrow in the photo above) allows you to adjust the shadows of your image by shifting the blackpoint of your image. By dragging the triangle slider to the right (as I have done here), you will increase the number of pixels considered black pixels (all pixels to the left of the triangle will not be black). This will darken your image overall. I’ll click the Reset button to reset the values back to their default.

The gray triangle (red arrow in the above photo) adjusts the mid-tones by shifting the midpoint – shifting this triangle to the left will brighten the mid-tones (as I have done in the image above), and shifting it to the right will darken them.

Finally, the white triangle (red arrow in the image above) adjusts the highlights of your pixels by shifting the white point – moving this triangle to the left will brighten your highlights (as shown in the image), while moving it back to the right will darken them.

Because this is a darker image, we will want to adjust our levels to make the image brighter. We can do this by counteracting our histogram. So, because we have taller bars in our histogram towards the left side, we can start by moving the white triangle to the left (red arrow in the image above). This shifts the white point of our image, or in other words it makes all pixels in our image to the right of the white triangle a pure white. By increasing the amount of white in the image, we brighten the image.

Next, I’ll brighten up the mid-tones by shifting the gray triangle to the left (yellow arrow). This shift my midpoint to the left, saying that all pixels to the right of this point are brighter than middle gray, and all pixels to the left of this point are darker than middle gray. Since we are increasing the number of pixels brighter than middle gray and decreasing the pixels darker than middle gray, our image becomes brighter.

For the finishing touch, I’ll drag my black triangle to the right slightly (green arrow) to add in some contrast. This will make our image slightly darker by increasing the total number of pure black pixels (all pixels to the left of the black triangle will become pure black), but this is fine so long as we don’t over do it. In fact, making bright pixels brighter (which we did earlier) and dark pixels darker (which we just did) is how we get contrast.

I can check the “Split Preview” option (red arrow) to see a before (right side of the split line) and after (left side of the split line). I’ll uncheck this option after I’ve viewed the comparison.

Red Channel

I’ll now move on to the red channel of the image by clicking the Channel dropdown and selecting “Red” (green arrow in the photo above).

Like with the Value channel, you’ll see a histogram under “Input Levels” (outlined in blue in the photo) as well as three triangles to adjust these levels. The only difference is that instead of adding or removing brightness, you are either adding red or removing red (removing red adds the color cyan to your photo). You can see that the gradient is going from black to red instead of black to white (yellow arrow in the photo).

You can see that our red histogram is skewed left, which means we have more reds in the shadows of our image and hardly any in the highlights. To fix this, we can add red to the highlights by shifting the highlights slider to the left, add some reds to the mid-tones by shifting the mid-tones slider to the left, and add some contrast to the red channel by shifting the shadows slider slightly to the right (this will add a touch of cyan to the shadows).

Green Channel

It’s time to switch over to the green channel by going to the Channel dropdown and choosing Green (yellow arrow in the image above). The same principle applies here – with the only difference being that we are either adding or removing green (removing green will add magenta to the image).

The histogram here is once again skewed left, so we have lots of green in the shadows and hardly any in the highlights.

I should note that we don’t always need to offset the histogram. In many cases, you may simply want to lessen the presence of a color in your image to achieve a certain tone or color balance. In my case, I don’t typically like adding tons of green to my photos.

So, for this image, I added a small amount of green to the highlights, removed green from the mid-tones by shifting them to the right (which added magenta to the mid-tones), and removed a touch of green from the shadows by shifting this slider to the right (adding magenta to the shadows – as you can see in the image above).

Blue Channel

The last channel in the Levels tool is the Blue color channel. You can access this channel via the “Channel” dropdown (red arrow in the image above). Again, this channel abides by the principles of all the other channels in the levels tool, but you are either adding or removing blue to the shadows, highlights, or mid-tones of your image (removing blue will add yellow to your image).

For this channel, I brought in the highlights slightly (adding blue to my highlights), then shifted my mid-tones to the right to add yellow, and shifted my shadows to the right slightly to add yellow to them as well.

Checking the “Split Preview” option one last time (red arrow in the image above) allows me to preview a before and after will all my changes. I’ll click OK to apply them to my image.

Step 3: Adjust Shadows-Highlights

The next edit I’ll make to my image will be via the Shadows-Highlights tool. I can access this tool by going to Colors>Shadows-Highlights (red arrow in the image above).

This tool allows you to re-balance your photo by adjusting the exposure of your shadows and highlights with minimal effect on the mid-tones of the image. Typically, you will find yourself increasing the exposure value of the Shadows and decreasing the value of your highlights. The extent to which you do this will depend on the image you are working on.

In my case, I increased the Shadows to around 50 (red arrow in the image above). This brought out some of the detail in the shadows of my image. Note that any value greater than 0 will increase the exposure for your shadows, and any value less than 0 will decrease the exposure.

On the other hand, I decreased the exposure value of my highlights to around -40 (blue arrow in the image above). This brought down some of brighter highlight values in my image. Although you must remember that this image didn’t have a ton of bright highlight values to begin with, so the effect wasn’t that intense. For the highlights, anything less than 0 will decrease the exposure, and anything greater than 0 will increase the exposure.

Finally, I can shift my white point by dragging the “shift white point” slider either left or right. If I shift it left, my image will become darker. This is because we are decreasing the number of white pixels in the image (just like when we shifted the white point with the Levels tool). Conversely, if I shift this slider to the right the image will become brighter. This is because we are increasing the number of white pixels in the image. In this case, I shifted the slider it to the right (yellow arrow in the photo above), making the image brighter.

I’ll click OK to apply my changes.

Step 4: Adjust Saturation

A common image adjustment in photo editing is adding or removing saturation from your photo. Saturation is the intensity of colors, so adding saturation is increasing the intensity of the colors in your photo, while removing saturation is decreasing color intensity. If you remove all saturation from a photo, it will convert a color photo to black and white. The official term for removing saturation from a photo is Desaturation.

To adjust the saturation of a photo in GIMP, go to Colors>Saturation (red arrow in the image above).

This will bring up your Saturation dialogue, where you can increase the scale of saturation (increase intensity of colors) by dragging the slider to the right (shown in the photo above – notice how much more colorful the photo looks)…

or decrease the scale of saturation (decrease intensity of, or desaturate, colors) by dragging the slider to the left (shown in the photo above – notice how color has been removed from the photo).

You can also use the dropdown below the slider to choose the color space for the saturation – I recommend sticking with the “Native” option (red arrow in the photo above), which is the default option, unless you have a specific reason for going with another option.

In my case, I want to turn the saturation of my photo up slightly to bring out the colors in the image. So, I’ll click and hold my mouse on the scale slider and will move it to the right. This will increase the scale value of my slider by a larger increment – if I wanted to increase it or decrease it by smaller increments I can simply hold down the alt key on my keyboard as I drag my mouse. This action is known as a “key modifier.”

For even more precise increments (i.e. to increase or decrease the value by .001), I can hold the alt key on my keyboard while hovering my mouse over the scale slider and use my mouse wheel to scroll up or down (this is another key modifier).

In this case, I went with a value of 1.175. Anything above 1.0 will increase the saturation, while anything below 1.0 will decrease the saturation. I’ll click OK to apply the changes.

Step 5: Spot Heal Using the Heal Tool

Now that the image’s brightness, contrast, and colors are, for the most part, how we want them, we can move on to retouching our model using “spot healing” tools.

In other words, these tools allow me to fix small problem areas such as acne, scarring, wrinkles, etc. If you are looking for a more in-depth way to retouch a subject’s complexion in a photo, I recommend checking out my video tutorial on the subject.

For this photo, I will only use the Heal tool as I don’t have any major repairs or touching up that need to be performed for this model. To grab my heal tool, I can hit the H key on my keyboard or can click and hold on the Clone Tool tool group in my Toolbox (red arrow in the above photo) and select the Heal tool from this group (blue arrow – tool groups are a new feature introduced in GIMP 2.10.18. If you are using an older version of GIMP, simply click on the Heal Tool icon in the toolbox).

Now that I have my Heal tool selected, I’ll hold the ctrl key and use my mouse wheel to zoom in on my image to the area I wish to heal.

The Heal tool is a “paint tool,” which means it uses a paintbrush to apply its effects to your image. So, once you have your Heal tool selected, your mouse cursor will show a brush head (red arrow in the image above). This brush head indicates the size and shape of the area you will be healing. You can change the brush head in your Tool Options by clicking the “brush” icon (blue arrow).

You can also adjust your brush head settings over in the Tool Options. I recommend having a soft brush (meaning the Hardness value is set somewhere below 50 – yellow arrow in the above image) – this will help your effects blend better as you paint them.

I also recommend setting the size of the brush to be about the same size as the area you are healing. To do this, hover your mouse over the area you wish to heal, then use the left or right brackets on your keyboard (“[“ or “]”) to decrease or increase the brush head size.

Once your brush is set up to your liking, you’ll need to grab a “source” area for the Heal tool by holding the ctrl key and clicking on an area of the complexion that is close in color to the area you are healing (red arrow in the image above). There will now be two brush heads.

Once a source area is selected, you can then click and paint with the Heal tool on what’s called the “destination” area. The destination area is the area you are trying to fix.

The Heal tool works by taking pixels from the source and destination areas, then using an algorithm to produce a new set of pixels that no longer contain the artifact (i.e. a scar or zit) you are trying to get rid of. It essentially blends the pixels together to produce a more convincing result.

In this case, I used the Heal tool to remove a small scar on the model’s forehead (red arrow). You can use this tool to remove a variety of small artifacts, imperfections, etc. in your image.

If you are looking to remove a background from your image, I recommend checking out this tutorial. If you want to remove large objects from your image, you can check out this tutorial.

Step 6: Sharpen Your Image

We’ve made the bulk of our image edits, so now we can move on to sharpening our image. There are many methods for making your images sharper in GIMP, with some being more complicated than others, but I’ll cover what I think is the easiest (and still a very effective) method for image sharpening: Unsharp Mask.

To sharpen your photo using this method, go to Filters>Enhance>Sharpen (Unsharp Mask). This will bring up the Sharpen (Unsharp Mask) dialogue.

There are three sliders here – Radius, which essentially controls the size of the area considered an “edge” for sharpening, the Amount, which is how strong the sharpening is, and the Threshold, which allows you determine the point at which GIMP considers a detail in your image an “edge” to be sharpened (sharpening mostly occurs by GIMP finding edges in your photos and adding contrast to those edges).

It is recommended when sharpening your photos that you do so while the image is at full-resolution – so before performing any kind of scaling/resizing of your image. The higher the resolution of the image, the more you can turn up the values of the sliders for a sharper result. For smaller resolution images, the default values will probably do fine (Radius set to 3.0, Amount set to .5, Threshold set to 0).

When it comes to higher resolution images, such as the image in this case (which is 5184 pixels by 3456 pixels – indicated by the red arrow in the image above), you can turn the values up more and get a better result. For example, by bringing the Radius up to around 4.5 (blue arrow) and the Amount up to around 1 (yellow arow), the image now appears sharper (it may be hard to see in the screenshot since I compress/scale the screenshots for the article and they lose quality).

If I wanted to lessen the sharpening effects on smaller details (usually in the subject’s complexion – such as acne, wrinkles, etc.), I can simply drag the Threshold slider to the right. This will still apply sharpening to larger details but will remove sharpening from those smaller details. I don’t typically use this feature, but it’s there if you need it. I’ll keep Threshold set to 0 for this photo.

I’ll click OK to apply the sharpening.

Step 7: Crop Your Image

If your image needs to be a certain aspect ratio, or you simply want to crop out unwanted areas in your image, you can crop your photo with the Crop tool.

To access this tool, hit shift+c on your keyboard or clip on the Crop tool icon in your toolbox (this tool is on its own – its not grouped with other tools – denoted by the red arrow in the image above).

Now, you can draw your crop on your image by clicking and dragging your mouse across the area you want to crop.

Or, you can go over to the Tool Options and customize your crop area. For example, if I want the crop to be a certain aspect ratio (which is the ratio of the width to the height), I can check the “Fixed:” box (green arrow) and choose “Aspect Ratio” from the Dropdown.

In the box below the dropdown box I can enter in the desired aspect ratio (blue arrow). Some common aspect ratios include 16:9 for HD, or 4:5 for Instagram. I typed 16:9 for this image.

I can also add guides inside my crop tool (yellow arrow) to help me position elements of my photograph inside the crop area. In my case, I have the guides set to “Rule of Thirds,” which divides my image up into 3 equal parts.

Now that I have my Crop area customized, I’ll click and drag my mouse across the image. If I need to increase or decrease the size of the crop area after I draw it, I can click and drag on any of the transform handles that show up when I hover my mouse over any of the corners or the sides of the crop area (red arrow in the image above).

I can drag the crop area until it reaches the boundary of my image. If your crop continues passed the boundary of the image, make sure the “Allow growing” option is unchecked in the Tool Options (green arrow).

After you have positioned your crop area, click once inside the crop area to apply the crop.

Step 8: Add a Vignette

The next step in editing your photo is to add a vignette. This is purely option, of course, but it helps make your image look more professional as well as draw the viewer’s eye to the main subject of the photo.

To start, I recommend creating a new layer (red arrow in the above photo), naming it “Vignette” (blue arrow), and filling it with a transparent background (yellow arrow). You can place the vignette on this layer instead of directly on your new image, which allows you to maintain a bit more control.

After you’ve created your new layer, go to Filters>Light and Shadow>Vignette. This will bring up the Vignette dialogue box.

There are many settings here to help you adjust your vignette. You can select the color of your vignette by clicking the “Color” box (blue arrow) or using the eyedropper tool to select a color from your image (I typically use a black vignette).

The Radius slider helps you increase or decrease the size of the vignette (red arrow). The Radius refers to the measurement of the very center of the vignette to the very outer edge of the vignette. The larger the radius, the larger this area and therefor the larger the vignette. I typically increase this value until my vignette is lightly visible in the corners (you don’t want a vignette that draws too much attention).

The Softness slider determines how soft the edges of your vignette will be (red arrow). If you make them too soft, the edges of the vignette begin to cover large portions of your image making it darker. If the edges aren’t very soft at all, then the vignette basically becomes non-existent (if the area where the edges start is located outside the image boundary) or creates a visible harsh line (if the area where the edges start is located inside the image boundary).

The Gamma is the rate of the falloff of the vignette as it goes from your color (in this case black) to transparency. Adjusting the slider to 0 will make your entire screen black because there will be no fall off from black to transparency, whereas adjusting the slider to a very high value will make the vignette essentially disappear because the fall off happens too quickly. The value you set for your photo will depend on the photo itself as well as your vignette preference.

The Proportion slider allows you to set the aspect ratio of the vignette relative to its proportion to your image. A 1.0 proportion simply means the vignette will have the same aspect ratio as your image.

The Squeeze option allows you to make your vignette squished in a vertical or horizontal direction. If you want to narrow your vignette, this is a good option for you (I typically do not use this setting).

The Center X and Center Y sliders allow you to change the center point of your vignette. By default, the center of your vignette will be the exact center of your image. If you want to shift the vignette’s center to the left or right, use the Center X slider. If you want to shift it up or down, use the Center Y slider. You can also click the mouse pointer icon in this section to manually click on your photo to set the location of the vignette’s center.

Finally, you can use the rotation slider to rotate your vignette around the center.

When you are ready to apply your changes (you can see my settings in the photo above), click OK. To reiterate, I typically keep my vignettes very subtle on my image. Strong vignettes have their place – but in most cases you don’t want your audience to be able to see there is a vignette on your photo. It should look like the lighting naturally falls off around the outer edges of your photo.

Step 9: Scale Your Image

The last step in our photo editing process for GIMP is to scale your image to the desired size. This step is also optional, though it is commonly performed in order to make the final image size more manageable or to fit restrictions of uploading sites.

To scale the entire image (and not just a single layer), go to Image>Scale Image.

This will pop up the Scale Image dialogue box. Under “Image Size” (red arrow), you’ll see the current width and height of your image. To the right of these values is a chain link icon (yellow arrow) that allows you to lock or unlock the current aspect ratio of the photo (I recommend always keeping this locked). Finally, to the right of that, you have the units for the measurements displayed (it will be set to pixels by default, but you can choose from any of the available units by clicking on this dropdown).

In my case, I’ll scale the image down to a width of 1920 pixels (blue arrow). When I hit the tab key on my keyboard, because the chain link icon is locked, the width will automatically adjust to its corresponding value based on the image’s current aspect ratio (which we cropped to 16:9 with the crop tool). The new value for the height is 1080 pixels.

Below the width and height you will see x resolution and y resolution. Here, you’ll find your image resolution in pixels per inch (ppi) – or whatever unit your resolution is set to. This section really only pertains to anyone looking to print their photos as it is converting digital units (pixels) to a physical unit (i.e. inches in this example). All you need to know is that 300 pixels per inch is considered a high resolution and will print better than a resolution below that.

Because I am not planning to use this photo for print, I’ll keep the resolution setting to the default of 72 ppi.

The “Quality” section (red arrow) determines the method for scaling your photo. Clicking on the dropdown box next to Interpolation (green arrow), you’ll see my options range from “None” to “LoHalo.” When resizing your images, I recommend using the LoHalo or NoHalo options (highlighted in blue) for the best results. The “None” option will be the fastest if you are scaling your image in a hurry, but it will produce noticeable quality loss when scaling your image. Linear and Cubic are better “speed” options.

Interpolation, to define it as simply as I can, is the method for which GIMP removes pixels from your image during scaling down or adds pixels when scaling up. For more information on this subject, check out my Scaling Images with Minimal Quality Loss tutorial.

I’ll select LoHalo as my Interpolation method and will click Scale to scale the image. My new image dimensions now display at the top of the image window.

Step 10: Save and Export Your Image

To save my image with all the original layers intact, I can simply go to File>Save and name my file.

Make sure your file name ends in .XCF (red arrow), which is the native file format for GIMP. I can then navigate to the folder on my computer where I’d like to save the file (once again using the “Places” section – outlined in green above – and double clicking on folders to enter those folders). Once I have found the location where I’d like to save the file, I can click Save (blue arrow).

On the other hand if I want to export my image to another file type, such as the commonly used JPEG file, I’ll need to go to File>Export As.

Once again, I’ll need to name my image and end it with the file extension I’d like to export it to. For example, I’ll add “.jpg” to the end of the file name to save it as a JPEG file.

You can always expand the “Select Filetype (By Extension)” section near the bottom (red arrow) and browse various file types you can export to if you aren’t sure what file extension to use. Once you find the filename you want to use, click on it and the file extensions (blue arrow) will automatically be added to the end of your filename.

After locating the folder where you’d like to export the file, click the Export button (green arrow).

This will bring up a dialogue for the file extension you chose (each one is different). Choose your settings and then click “Export” again.

That’s it for this tutorial! If you like it, you can check out my other GIMP Help Articles, GIMP Video Tutorials, or GIMP Premium Classes and Courses! You can also get more with a Premium Membership to Davies Media Design, including access to my GIMP Help Center App, exclusive video tutorials, and unlimited articles on my site.