patricej

i can't think of a solution to the "problem" other than asking a moderator to edit your thread's title.
i think Tartan's suggestion is spot on, really.
post a new thread with the updated photo(s), information, etc, and - if you think it necessary - a link to the original thread.
since we can customize the number of posts displayed per page, my page 20 and your page 20 might not bring up the same set of comments, so a title modified to say "update on page [so-and-so] would create confusion for some people.
it's also true that a lot of people wouldn't want to page back and forth [especially within the same thread] between the old and new photos to compare between the original and current status of whatever we are updating. a new thread would attract more viewers.