I guess the question has long since been answered but I figured I'd mention what I use too. I came across
a plugin for Paint.NET that works fairly well, you just select a box on the canvas and select animation under effects and it brings up a window that animates however many frames you'd like after that box with the possibility of a border between frames, you can also export as a .gif but it's still under development and tends to compress the animation poorly.
Your program seems pretty useful Arne, I like the choice of name too.
