I am positive that someone has already asked this at some point but I thought I'd post a thread real fast since I don't want to go scouring the forum for an old topic on this matter.

So I know how to do four things on GIMP, really. These four things are selecting, cutting, moving the selection, and rotating it. Now, after I'm done doing these simple tasks, every time I save my modified gimp image, the pixels of the selection are messed up. As in, around the borders of where colors change, the colors are no longer solid, but some sort of weird transitional deal where they're all different.

Do you know what I mean?

This is especially annoying when my primary tool is Microsoft Paint. Every time I use GIMP to do something, I have to go back over with the pencil tool or the bucket tool and recolor all of the pixels that for no apparent reason changed to different color shades. Does anyone know how to get around this problem?