The whole use of images thing blew up a couple of weeks ago, but I haven't seen anything on MR about it, so here's some links:
Roni Loren's blog, the source - http://www.roniloren.com/blog/2012/7...your-blog.html
Vacuous Minx with some advice - http://vacuousminx.wordpress.com/201...might-want-to/
Jane at Dear Author - http://dearauthor.com/features/lette...-for-bloggers/
Basically, any images you use on your blog, Facebook, Tumblr or wherever can get you in trouble. There's some nice links on Dear Author to information on "Fair use" as applied to writings as well.
It was also pointed out that because Loren is an author, her usage of images on her site counted as "commercial use," so that's a butt biter right there. Which is why people are removing any possible trouble images from their author blogs, Pinterest, etc. If you've got anything like that up, you're better off going back and checking through any images you're using.