I’ve noticed on a couple of my sites, Google Image Search taking up a lot of bandwidth. This helps explain it a bit. I’m not sure if it’s worth it at all. On one of my sites, they were pretty much just hotlinking my images, so I disabled hotlinking. The site wasn’t getting very good rankings in the search anyway, and still isn’t. If Google is going to take my bandwidth, I’d appreciate if they’d at least give me a good SERP in return.
*disclaimer: if any Google employees ever read this, I’m being sarcastic with that final remark, please don’t ban me.