Requiremens for GIF-frames are simple: 1) They must have single size. For example, first frame is 200x70 pixels - and all another frames must be 200x70 pixels. 2) IT IS WILL GOOD IF they all will have SINGLE PALETTE (then in animation will not be writed individual palette for every frame, this palette have size 1 Kbyte, and for 50-frame animation - can add 50 Kbyte to GIF-animation file size. If frames have SINGLE palette - then this palette will be writed as GLOBAL palette for all frames in GIF-animation). In PaintCAD it is simple to create GIFs with single palette: open gif, select method of adaptation to uni-palette ('JoyRight'-'Adaptation'), next press '*'-'UNI-palette' - and palette transforms into UNI, and after it you must save gif to his old place (overwriting old file with non-uni palette) (or you can save to another folder, if old gif you need also).