GIF ? Thumbnail or Image

Hi,
Is there anyone who know how to add an animated GIF on a Thumbnail ?
Each time I try, I get the message "JPG, PNG, or GIF only." I am using .gif pictures but nothing seems to work.
It used to work on the previous version of RS but not anymore. Is it a technical problem ? Is anyone have any solution or answer to this problem ?
Thanks

You aren't the only one having those issues. >_

I know ... I will just love that someone can read my message (and the messages from other people who have the same problem) and find a solution, or even better : fix it !!
Thanks by the way (^o^)//

Also tried uploading a GIF today, and it said for Main image it accepts JPG only? :( And for Image #2 it says "JPG, PNG, or GIF only." when my img is clearly a .gif it still doesn't accept it. My old uploads of animated gifs are still working fine, I just can't update or upload a new one.

Hi all got this to work for me!
On my Mac, you just rename your animated .gif file extension to .jpg and save.