I've recently received some requests about copyright issues and getting permission for the use of photos to use in publications. Stanford University Libraries has a great website about Copyright and Fair Use issues:
Permissions and related issues are dealt with in the Copyright Overview section, at the upper left, or from the "Overview" tab, as well as in the sections "Charts and Tools" and "Libraries and Education."
Librarians cannot give legal advice, but we can point you to these resources. It is the responsibility of scholars and individuals to make every effort to comply with laws and standard practice. Open source and "copyleft" practices are gaining ground in the academy, and you may want to consider these with your own work. Creative Commons is one way of clearly maintaining copyright on your own works and ensuring proper attribution, while also making it easy for others to use your research. Creative Commons proposes several types of licences that you can apply to your work, offering varying degrees of use restrictions.
Copyright and fair use is about correctly using materials in your own work, and making sure that your rights as a scholar and content creator are respected by others.