In Search of Answers: Digital Images

This week I will try to find answers to the following questions I have regarding the use of digital images in the classroom:

1. Can I use any image (for non commercial purposes) as long as I cite the source?
2. What restrictions apply to posting images on a personal blog versus using them in the classroom (eg. in handouts, powerpoint presentations, posters)?
3. Are there any additional restrictions that apply to the use of video?
4. How can I limit the use of my own images, such as those that I post up on the web?
5. Can I post photos of my students working in the lab? If so, what guidelines exist regarding this?
   
6. How do I search for copyright-free images?
7. What is the best approach for teaching students about good/ fair use of images they obtain from the internet?
8. Can you edit images that are not yours, and if so, do different permission guidelines apply to their use?