How do you handle storage space for users images?

I've dabbled with multisites a few times and recently decided to get serious about it. But the one biggest issue the keeps me up at night is how much disk space users will eat up by uploading images. I would like to allow users to create photo galleries, photo blogs, and of course add photos to their posts.

I'm using shared hosting to start, but will move to dedicated as soon as budget allows. Even then, I imaging users images will fill a 250 Gig drive in short time. How do you folks manage this? I really appreciate your suggestions.