I checked it out for that reason. Then I found a number of social images and began wondering why a lightweight CSS framework needed images for facebook, twitter, etc...

You mean the Social Icons in the Add-ons section? You don't need to include those, in fact, I believe they are opt-in, not opt-out.

Just checked and you are correct.

If you want something lightweight, I wouldn't go for Foundation either. Even after stripping out the unnecessary stuff, I found it overly obnoxious to style.

I ended up with the Skeleton framework after struggling with both Bootstrap and Foundation for a few days. It was a much better decision. I've also been eyeing Bourbon Neat lately as well.