If you're trying to stop the .GIF from corrupting by reuploading it at a different size, it's not going to work. KYM's compression is completely goat roped when it comes to .GIFs. There is nothing you can do to stop this and at this point I doubt that it will ever be fixed even if it can be.

The only thing you can do is put a note in the title telling people to go to the image page and click on the image to view the .GIF by itself since this is the only way to see a corrupted .GIF without corruption.