So, I am having a serious problem with GIMP. If I have downloaded a .gif, or have saved one previously, I can hardly edit them at all. The most I can do is draw plain lines with colors that already exist in the image. I cannot smudge them or chose new colors or anything. In the end I had to open the image with paint, dab in the colors I wanted, and then open as a .gif again. Still, things like smudge did not work at all, and of course opening with Paint ruined the animations.
Is there something I am doing wrong?