GIMP is also a legally free option on all modern operating systems.
I know some folks intentionally shy away from full(er)-featured software suites of this form, but maybe it's time to learn
I know the number of tool options can be daunting, and the default setup is not really well-suited for Shipbucket use. For this reason, I will be putting together a "GIMP lite" user profile that folks can download and apply to their install. This will hide all of the more confusing and less useful tools (although not remove them), which might help to ease the transition for our more stodgy users.
I'll try to get to that this week.