Lifehacker:

If you’re on the lookout for a digital painting tool and Photoshop is too expensive, Krita is a fast, free, and open source art tool that was developed by artists looking for something that met their needs without a ton of bloat or overhead. Plus, it’s completely cross-platform.

When we say “photoshop alternative,” we don’t strictly mean an alternative tool to help you manage photos, color correct them, resize them, and get them ready to share. Sure, you could probably do those things with Krita, but the tool is really designed for artists looking for a painting application to create original digital art, web and print comics, concept art, and more.

As the article said, this won’t replace Photoshop completely but if your needs are specific and you don’t require the full power of Photoshop, this might be a good alternative for digital artists.