you can always post the pictures on a personal webpage or free posting site and provide the link to the site here
even though this site is setup to block direct links to outside url's and email addresses you can always alter the url prefix so the site script will not pick up on the url... i usually add some spaces to the w.w.w or http part and use preview post to insure it does not blank out the link. ;o)
Then whom ever wants to visit the link provided can just alter the link back to its original form and paste it into a new page in their browser header and go there to see them.

Note: I'm sure the reason behind disabling links, email addresses and pictures in the forum is to conserve server space as they do tend to build over time and utilize server space. Also there would of course be a security factor to consider for visiting outside url's and posting email addresses as bots do tend to pick these up, so keep this in mind when posting links (even self engineered broken ones).