I just open another browser window, go to one to my PB accounts, open the photo, then right-click on the photo in PhotoBucket et al, then click, "properties"...
Then copy the URL address of the picture.. Now go to your broswer window, the one in FSM, paste it in the "image" window (open it by clicking on the little film-strip icon) after you've open up a "reply" window....
Then click "insert" and it's done. You can do it as many times as you need in a thread, but be kind and don't post more than four or five per post... Takes forever to load more than that sometimes..