The easiest I've found (and what a lot of people seem do to around here) is to open an account with flickr.com. You can upload your pictures there. Then, when looking at an individual picture, there should be a button right above it that says "Share". Click that, choose BB format, and copy the offered link into your post here on ftp.
Uploading via the little button on the tool bar is easiest for me. You can also click and drag if you're using flickr (you do have to get to the "all image sizes" screen to do that, I believe).