If you are running a slower connection or just don’t care for these images, then there is an easy way to disable them. Follow the steps, and you won’t see anything but the first frame of the GIF animation.
1) Open Browser
2a) In address bar (Type: about:config)
2b) If you are running FF3, click ok to the message.
3) Find image.animation_mode
4) Change the value to none
If you have any problems, you can always just go back and re-enable the value to normal. No harm, no foul.
