lucy24 - 8:40 am on Aug 24, 2012 (gmt 0)
so you aren't even allowing the search engine bots to see those large images and that would mean you are preventing them from indexing those large images
No, where are you getting that from? Most robots come in without a referer, so they can index to their heart's content. The rewrite-- not redirect-- only kicks in when humans view the image in a search. That's when you get a named referer.
Why should they hog my bandwidth loading up a full-size picture? The thumbnail is identical in every way, just smaller. If they're interested they can go to the page and see the real thing in its intended environment.
There are some areas I do have blocked because I find that most visitors are simply looking for hotlink fodder. But those aren't anywhere near the galleries.