Don't be too surprised if it takes even a couple of months. Nothing to do with the gallery, more to do with how google finds out about your site and how it often it checks for changes.
If there is no other site on the net that links to yours then google probably won't even know it exists.
If you've had the rest of your site up and running for a while, but the pages don't change very often, then google will have worked this out as well and so it won't search through your site very regularly to look for changes.
In general, Google search out new sites once every 33-45 days, but it might not list them for another month or so.
It's a long process to get on google and even when you do it takes even longer to get a good ranking with results that'll actually bring in traffic because of the dreaded 'sandbox'
There are quite afew tricks that can give you a better chance of getting good results but don't try any of the cheap and nasty 'let's try and fool google with some clever cheats' type of tricks, because they'll probably find out and penalise you for it. Check out some of the
SEO forums for tips and tricks.