See:

• Bookmark Favicon Changer: https://addons.mozilla.org/firefox/addon/bookmark-favicon-changer/

that addon will only work for monday and tuesday, as FF 22 breaks it.

you can try this https://addons.mozilla.org/En-us/firefox/addon/identfavicon/

It works but is nothing like the original solution.

Its a pity that the Firefox Team broke the add-on repeatedly and never bothered to fix the base issue which is the adding and changing of the bookmarks icon should be a BASE feature of Firefox!

I had the same problem. The currently available plugins don't seem to work or don't do the job, so I came up with my own solution.

I created a blank html page and saved it to my hard drive in its own folder. In that folder, I also saved the favicon I wanted (in .ico format) and made sure the code for the page linked to it. I then viewed the page in Firefox to see if the favicon would appear on the page tab. It did, so I dragged the tab to the bookmarks bar, then edited the code for the page so that it redirect to the page I actually wanted to go to. Works like a charm! Not as good as having a dedicated FF function or plugin, but it does get the job done.

Now, if I could only find a solution that works for javascript bookmarklets.