Forum:"Invalid thumbnail parameters"?

"Error creating thumbnail: Invalid thumbnail parameters"

Wondering about the current error I'm receiving on editing / uploading ability details GIF files. I think I followed all the specified requirements for the file, though other things such as dimensions were not given to me.

The page displays "Error creating thumbnail: Invalid thumbnail parameters". The file is uploaded on the site, but doesn't display, and Google searches actually don't say anything beyond repeating the error phrase for reference (but not how to solve it).

The exact specs for the GIF are (image/gif, 8.05 MB, looped, 70 frames, 4.9s) 569×320(8.05 MB)

This is slightly bigger than other ability detail animations, but still within the acceptable limits I thought. What are the different options I have to resolve this?