I've been using mtpaint for editing images and sprites, but it bothers me that it has a very arcane functionality with selections and also lacks tools for drawing. All it has is the pixel tool and the fill tool. But I haven't been able to use normal image editors because they don't respect the image file's color palette.
I've heard some people use Photoshop or GIMP for these, but I don't know how they get the program to confine you to the palette. I have GIMP already and it would be a pretty big upgrade over mtpaint if I could get it to work, although it also has a very arcane functionality with selections.
People have recommended Aseprite, and that one looks very good, however it costs money and I can't afford it. I don't want just a trial version that will expire after a short time. I need something I can use in the long term.
What do you guys use? Can you give me some pointers?