Google image search is a great resource for finding pictures and images. Did you know that it is not necessarily legal to use those images in your work? Copyright laws extend to the internet and any image found on a website is the same as any found in a textbook. While some leeway is granted for educational purposes, its better to be safe. A great website for free photos that can be used by teachers and students is Pics4Learning. There own description describes it best, "Pics4Learning is a copyright-friendly image library for teachers and students. The Pics4Learning collection consists of thousands of images that have been donated by students, teachers, and amateur photographers. Unlike many Internet sites, permission has been granted for teachers and students to use all of the images donated to the Pics4Learning collection."
It is important to teach our students early that they need to think about where they get their resources and doing it legally. Teach by example and be conscious of your image choices.
If you are looking for clipart for worksheets and other printables, check out www.school-clip-art.com. This site offers easy to find clipart sorted by categories.