My Site is Growing - Have a Couple Questions.

Phil Boyd

Core license
Ok, while my site is nothing near as big as most of you guys is, it's getting bigger and there's a few things I'm going to have to tend to. It's currently on a shared hosting account with my other websites. My web host has assured me that as of now it's not a problem but I have a feeling it's not going to stay like that.
One thing is the size of the images users are uploading. Does Chevereto use anything to compress the images (like Gzip) or do I need to set that up? The users of my site are not the most tech savvy so I really don't expect them to worry about image size.
And one other quick question - I have a little over 100 members of which at least a dozen or so are just "spam" accounts with no images. How do you normally handle weeding out spam memberships from the legitimate accounts? Is it customary to just delete a 3-year old account that has never had an uploaded image?