Pixabay.com - Royalty-free Stock Images
An ID colleague shared the Pixabay site with me during the development phase of our project, and I found a lot of royalty-free images we used in the modules.
I enjoyed it so much I just uploaded a few of my photos and wrote a blog post about it here:
You'll find graphics, vector images, and illustrations in addition to photos.
Hope you enjoy this resource as much as I do.