GIMP is a fantastic free, open-source image-manipulation software.

The program has long had the reputation of being difficult to use and beginner-unfriendly. This is in large part to its historically utilitarian (and frankly ugly) GUI.

As of writing, the most recent stable release is version 2.10.38. Much thought has clearly been put into updating the UI. However, this was not the case when I learned how to use the program. I first encountered GIMP around version 2.7.1. It was a lot uglier back then, but I was a kid with no money or concept of piracy, so GIMP was all I had.

After all these years of GIMP being one of the first things I install on a new computer, and dare I say even a friend to me, I want to share what I've learned to help other people get into using this wonderful program. That's why I'm writing this tutorial.

1.1 The Goals of This Tutorial

Together, we're going to create a cool work of art by exploring many of GIMP's main functions, such as:

• Importing and exporting files
• Selection tools
• Colour adjustments
• Filters
• and Brushes

In doing so, you will become comfortable with navigating the UI and (hopefully) feel empowered to keep exploring the program and using it to meet your graphical needs.

Ready? Let's go!

For the purposes of this tutorial, I am going to walk you through how to make a image similar to the one below:

To do this, we are going to remix and stylize the information from a preexisting image. So, naturally, you are going to need an image to start with. I am using this image from the royalty-free stock photos website Pexels. You can follow along with the same image, or choose another that catches your eye.

There are alternative websites to Pexels out there, but beware of sites such as Pixabay that allow AI-generated content, as you cannot verify that the materials used in the creation of the image are royalty or copyright-free.

Once you have found and downloaded an image to use, it's time to import it into GIMP. Fortunately, this is exceedingly easy to do. All you have to do is drag-and-drop the image into the window.

Alternatively, you can use the import dialogue window by navigating to the top left of the screen and selecting File -> Open... From here, navigate to where you saved your image, and double-click it to open it.

Depending on the metadata of your image, you may be asked whether to convert or keep the embedded colour profile. This decision doesn't really matter for our purposes, but I'm going to click Keep anyways.

2.1 The Basic Layout

GIMP's workspace is made up of "docks" or sections that group functions and tools together. It is modular and customizable, but can appear intimidating or overwhelming at first. Fear not, I've broken it up into three main parts, outlined here in red:

From left-to-right, we have the Tools dock, the Image dock, and the Tabs dock. These are not necessarily their actual names or groupings, but this is how I will refer to them here for the sake of simplicity.

You will notice that I have also grouped the menu items in the top bar together (outlined in orange). This is because, although not in a dock, many of these menu items lead to more dialogue windows that contain functions and features that cannot be accessed anywhere else, and will be instrumental to our usage of GIMP.

You will also notice that the Tools and Tabs docks are split into two sections.

The Tools dock is split between a menu of all general-use tools, including the likes of selectors, brushes, and transform tools, and the associated options for each tool. Try clicking on different tools at the top of this dock, and seeing how the lower half changes. Brush tools will contain options for radius size, hardness, opacity, etc., while selectors such as the Fuzzy Select tool will contain options for selection thresholds. Right-clicking a tool will generally bring up a sub-menu of other tools that function in a similar way (i.e., right-clicking the Fuzzy Select tool will bring up the option to equip the Select by Colour tool).

On the other hand, the Tabs dock is split between two distinct tab windows, each with their own options of what tab to view. Different tabs will be helpful with different types of projects, but don't worry about them too much. For now, I reccomend switching the top tab to your Undo History, and your bottom tab to your Layers.

3.0 Alpha Channels and Transparency

I want to remove the sky from my image. When I downloaded my image, it was a ".JPG" which is a file type that does not contain an alpha channel, and therefore contains no transparency. If we start erasing parts of our image, it will look as if we're painting in sections of whatever colour our background colour is set to in GIMP. This is not ideal, so we must create an alpha channel on the same layer as the image in order to work with transparency, which will make our lives easier in future steps.

To create an alpha channel, navigate to your Layers dock and right-click the layer that contains your image. This will bring up a menu with a whole host of options, but we only want to click on Add Alpha Channel. Now when you erase, the background will appear as a grey checkered pattern. This is GIMP's way of representing transparency.

3.1 The Selection Tools

There are a number of tools at our disposal in our task of removing the sky.

By far, the easiest way to select a portion of your image is to use selection tools that work based on an algorithm, such as the Fuzzy Select and Select by Color tools. However, these tools are imperfect, and may require careful fiddling with their threshold sliders, or may just not work that well at all. Unfortunately, in my case, neither of these tools are useful as many parts of my image I do not want to select are too similar in hue and lightness to the sky.

Instead, I will opt for the superior but far more tedious option of the Free Select tool. To use this tool, all you have to do is click along the outline of the shape you want to cut out. The selection is only created when the two ends of the selection path are joined.

While using the tool, you can hold shift to snap the path along a perfect horizonal or vertical axis, which can be helpful when selecting large geometic shapes.

If you have a steady hand, you can hold down the left mouse button as you move the mouse to create an organic path.

If you make a mistake, you can adjust the path by clicking and dragging one of the circles that appear along the path.

For the purposes of accuracy, you may want to zoom into the image. I find the easiest way to do this is to hold CTRL and scroll the mouse wheel. Note that the viewport will zoom in wherever your cursor is in the Image dock.

Once you have finished deleting parts of your image, you are free to put whatever you like back there, be it a colour, a gradient, or another image. In some cases, you might also want to leave it transparent. For now, we won't add anything in the background, and come back to it later.

For this image, I want to change the colour-grading to stylize it and make it my own. In order to do this, we will be working within the various dialogue windows that we can access from the Colors section of the top menu. I reccomend clicking on each option here and dragging around the bars in each dialogue window to see what they do. If you don't like the effect, you can always click Cancel or hit CTRL-Z to undo it.

I am going to alter my image by clicking on Colors -> Exposure, increasing the blackpoint and decreasing the exposure, then inverting my image with Colors -> Invert and Colors -> Value Invert.

I now have something that already looks pretty neat: