ok, if you know computers, why are you talking about programming languages?  it's not the language that's an issue, it's the db design.  in any language, you'd have to change all your queries, and unless you were working very nicely abstracted solid class/object layer between the pages and the db (not usually the case with php development), it means rewriting all the pages.  if not, it would still mean rewriting all the relevant classes.  i have nothing to do with it, but i know what would be involved if it works like i'd guess, and it wouldn't be small, it would be an entire rewrite.

it would be even worse in a procedural language, because you wouldn't be able to have an mvc setup and each page working with the images would need to change.  what sort of programming do you do?  how do you get to do scientific programming without having to understand db design?  i ask only because all the friends i have who've worked in scientific programming have had to deal with databases.

edited to say:
let me qualify this, actually.  if this site was built using a framework, like django or ruby on rails, the relationship between objects and tables in the database would be handled automatically.  i'm a lot less sure how much of a change it would be in that case, but i still wouldn't want to do it. no matter what, you're talking about switching around hundreds of thousands of entries.  and again, maybe it was built with the possiblility of multiple galleries per image, but rendo only uses one.  but that's not where i'd put my money.