Why is Boot Drive Filling Up?

[deckeda]

sekker wrote:
... Another boot drive space hog is photostream, but I don't think you have that turned on if you are using SL. But if you have the latest iPhoto, I'd check. That's a terribly poorly written program in my experience, comes with my issues than ever.

I looked inside the library package file but didn't notice them. I've created a shared photostream but most of the images weren't added by me. If I right-click on one in iPhoto there's an "Import" feature; apart from low res previews I don't think they are stored on my Mac.