Hey, I'm still figuring it out myself. Check out my last posting to '63 220b parts.
There are at least two ways to post. First, find yourself one of the FREE photo hosting sites on the net, I used Webshots.com. Set up an account, make an album, upload photos to it. I uploaded six at approximately 2.5 megs each.
Then, when you post to the Forum, write your post and when you're ready to link to the photos use the "Insert Image" or "Insert Hyperlink" function in the Toolbar at the top of the posting screen. I used the Hperlink function this last time as I simply linked to the Webshots address where I stored my photos. The Hyperlink function is the one with the icon of the "World & chain".
Beyond that I can't think of anything else to do. If you try it and have problems post and I'll try to be more explicit.