Here is the gif I want to submit, there's any problem on it? I ripped the bottom part where the shadow could be seen (made with a filter)

The image is auto-dithered, either from a color-reduction or the gif-anim process, you'll need to figure out how to turn that off. The signature seems to have been applied via semi-transparency which isn't quite ok either. You should have control & knowledge of every pixel and color.