Need function that converts Java RGB bufferedimage to GIF bufferedimage but with colormap that is bigger than 256 colors.
Does anybody know if there are exist such library or a self-written function?
..with colormap that is bigger than 256 colors.
No can do. GIF supports a maximum of 256 colors. Use PNG instead.
So to answer your specific question..
Does anybody know if there are exist such library or a self-written function?
No it doesn't exist.