Sim, você pode usar o Privoxy para isso. O bônus é que esta é uma ferramenta no nível do sistema, para que você possa usá-la em combinação com qualquer navegador.
De o manual :
8.5.12. deanimate-gifs Typical use:
Stop those annoying, distracting animated GIF images.
Effect:
De-animate GIF animations, i.e. reduce them to their first or last image.
Type:
Parameterized.
Parameter:
"last" or "first"
Notes:
This will also shrink the images considerably (in bytes, not pixels!). If the option "first" is given, the first frame of the animation is used as the replacement. If "last" is given, the last frame of the animation is used instead, which probably makes more sense for most banner animations, but also has the risk of not showing the entire last frame (if it is only a delta to an earlier frame).
You can safely use this action with patterns that will also match non-GIF objects, because no attempt will be made at anything that doesn't look like a GIF.