I still wonder why Mozilla FireBird has no option to turn off animated gifs. I mean, it's not like they are Netscape or AOL, or what :) But because FireBird still has no GUI for this, it doesn't mean there's no support for stopping animated gifs.

To change this in firebird:

- type about:config in the location bar

- scroll down to image.animation_mode

- set to "none" for no animation, or "once" for a single loop

- restart your browser