Please read this blog about an Author/Blogger who was sued for using a photo she found on the web. Unfortunately she was unaware that the photo was copyrighted and the photographer sued her. She learned a great deal about the interworkings and other law pieces to using copyrighted photos/material the hard way. She posted her experience so that she could educate others so they wouldn't have to endure what she did.
Ever since I started seeing the posts on FB and Twitter about individuals stealing artwork, photos, books, and etc. and claiming them as their own, when the work is someone elses, I've been very leery of posting, saving, or etc. anything that doesn't belong to me. I know I know some may say...oh you're just parnoid, it won't hurt anything, but after reading the post by Roni Loren, I feel my paranoia is warranted.
The biggest lesson learned: "I didn't know" doesn't keep you from getting sued or having to pay!!