No, you're correct, JomSocial is no longer supporting Joomla 1.5 in their newest releases, as far as I know. Didn't even notice I was in the Joomla 1.5 forum when I posted that.
Unfortunately, I don't have any other great suggestions. You may want to contact JomSocial to see if they have any solutions, or there may already be a post in their forums with how to make each pciture URL unique, but I'm just not sure.
Hopefully, that at least puts you on the right path though. We'll definitely agree that a migration isn't the most appeasing thought. We're in the process of planning one out for this site right now... ughh.
Thanks,
Alex