In chrome 35 running on Mavericks, while using an animated gif as a background, gif only animates while user is scrolling, it's really strange, this only happens if the background is fixed, and only after the first element with a gif background
here is a demo I placed in codepen
I believe it is not a bug but rather a the way Google Chrome is made.
Firefox and other browsers have ways to stop the GIF's from animating while Chrome doesn't (Unless you use extensions.)
Here is a feature in Firefox for changing the settings of animated GIFS:
about:config
in the address bar then press
Enter. Click the “I’ll be careful I Promise”
warning button to reveal
a long list of preferences.image.animation_mode
(its default value should
normal
).none
to completely
disable image animation.once
instead to make the
GIF images animate only once.However, in Chrome, There is no menu option to disable animations. Even when using Chrome's extensions to disable GIF extensions, as soon as you scroll up/down the page the animations play once whilst a new screenshot is overlaid.