zabalex and qcloud, thank you for your responses!
Both are great information. I've looked at the ever-popular Nextgen in wordpress and with hacks (another plugin) I can manually dictate a page for each photo to open in, then manually create each page. I'm looking at converting a site with a few thousand pages - that's a lot of pages to recreate!
I guess there is no way around creating all those pages again one by one in a CMS. That's what I was really wondering.