Works fine except for tab-icons Rated 1 out of 5 stars
I don't like this plugin anymore because it screws up the icons on the tabs. If this could be fixed it would be okay.Too bad the author of Favicon Picker 3 quitted because of Favicon Picker 2's author. I bet he would have fixed it already.
I now switched to Favicon Changer https://addons.mozilla.org/de/firefox/addon/bookmark-favicon-changer/ which does not handle tab icons but at least it doesn'tscrew them up. Additionally it allows me to change Bookmark Folder Icons!