GIMP
Drop-in replacementFreeThe same program you already use, installed from the app store instead of an installer file.
Your files: Opens your existing .xcf projects unchanged, plus JPEG, PNG, TIFF and .psd files.
Does GIMP run on Linux?
Verdict: Yes
Yes. GIMP started life on Linux and the Linux version is the one the project builds first. It is free, it is in every app store, and it opens the same files as the Windows copy you already have.
If you have been using GIMP on Windows, this is the easy part of switching. GIMP is free and open source, published under the GNU GPL, and Linux is its home platform. Recent releases are on Flathub as org.gimp.GIMP, and most distributions also carry it in their own app store.
Nothing about the program changes. The same toolbox, the same layers and masks, the same filters, the same keyboard shortcuts. Version 3 brought a tidier interface and non-destructive editing, and the Linux and Windows builds track each other closely.
Bring your settings with you if you can. GIMP keeps brushes, scripts, plug-ins and preferences in a folder under your Windows user profile, and copying those files onto the Linux machine saves you setting everything up twice. Plug-ins written for Windows only will not load, but most are scripts that work anywhere.
Your .xcf project files open exactly as they are, and so do JPEG, PNG, TIFF and .psd files. There is no conversion step and nothing to buy.
GIMP on Linux, and alternatives
Krita
Different way of workingFreeWorth knowing about if what you actually do in GIMP is painting and drawing rather than photo fixing.
Your files: Opens .psd and common image formats. It does not open .xcf files.
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