GIMP
Official screenshots
GIMP provides layers, masks, selections, filters, scripting, and broad format support for scanned-art cleanup, texture finishing, and batch processing.
Why use it
It is free, cross-platform, and highly automatable, making it dependable for everyday image cleanup and conversion in a game art pipeline.
Where it fits
Use art, animation, audio, levels, and narrative to make the game easy to read and its world convincing.
What to check
Its interface differs from Photoshop, while high-end prepress, some proprietary file interchange, and native animation workflows remain limited.