Thank you. This does pause GIFs - both globally (then refresh the page after a change), or per picture (from the context menu from right click or Ctrl+Click).

Arturo (the developer): Please consider adding Resume/Continue menu entry to the context menu.

Giving a 3 star because it doesn't actually pause the .gifs. It seems that it stops them from playing all together. I'm looking for a tool that will pause and then play gifs, to slow down the playback of a .gif. Unfortunately, this doesn't do that. But, otherwise a good and simple way to stop .gifs from playing in the browser.