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> I should give it another chance by judging it as an editor.Maybe it offers more options than the ones I know.
Well, it is often seen as  inferior  open source attempt at photoshop, so it just might! It certainly can do more than paint. 

Here is a tool I've used in a few tests but I don't think I ever used it an edit. You make a cage around an area and then can move the nodes to stretch it or shrink it. Hence the name Cage Transform.