I tried Gimp but from an UX Perspective it is just a horrible mess. Its ways are so idiosyncratic its unbelievable. Power to those who use it, but it is hardly surprising that it never gained traction in the graphics industry.

Affinity Photo is the first true contender; It optimizes for reliable and recognizable workflow, and the devs are committing to keeping it lean.

I wish there was an foss alternative, but there isn’t. I would love to see an app build around image editing like Blender is doing for 3d.