Hi Lesley,
To post the actual photo here, if Pbase allows it, look for the "embeddable forum" link and copy that. It should look something like this:

The code looks like this:
[ url=http://www.wagsandwhiskersphotography.com/Proofs/American-Eskimos/7482020_TwBGt#912944768_PTutw-A-LB]/American-Eskimos/Pooh-the-Ball062310213/912944768_PTutw-S.jpg[/img] [/url]
you need both the [img] tag and the [url] tag.
If Pbase doesn't have an embeddable link, you can just post the link in the body of the post like Preston showed.