Following various blogs and having attended photography classes have enlightened me to the importance of respecting other people's creative works. Images that have been taken or "borrowed" from other internet sites may seem innocent enough until the author or photographer complains.
Ever since then I have started using Wylio for my blogging photo needs.
Wylio is a site that offers free creative commons pictures - free for use. Just type in keywords and pick from their wide array of photos. Instructions are also included on how to insert your chosen photo.
Visit Wylio for all your blog photo needs. =)