In Chrome, I was able to directly post an image from my clipboard into the Facebook chat, but this doesn't seem to work in Firefox. This is actually a feature that's pretty useful for me, so I might just head back to Chrome if there's no solution. I don't want to have to go to an external website in order to upload images.

Example: I would simply hit the print screen button on my keyboard, then ctrl+v inside a Facebook message/chat. This cannot be done in Firefox.