Photos For Class: a site to find and cite Creative Commons-licensed images. When you find the photo you want to use, click the download link below the image. The attribution will appear on the photo.
Pixabay: You can search using keywords or you can browse the gallery of images. Download the image you want to use.
Creative Commons: I'll be teaching the older students how to understand and use the various Creative Commons licenses.
Google Images: I'll be teaching the students how to use the Search Tools - Usage Rights - to obtain public domain images