Authors need to think carefully when using the work of others. Online availability and submission to Proquest (a commercial company) make close attention to these issues more important to authors of theses and dissertations.
Staff in the libraries do not offer legal advice. Decisions about using the work of others, appropriate citation, and getting permission when needed are the author's responsibility.
Links and tips below may help get you started. You are welcome to send details about your concerns to Copyright Help for information and links to resources that can help with your analysis.
Is the material I want to use covered by copyright?
Is there an exception that covers my intended use? Is my use a "fair use"?
How do I seek permission? Note: Denial of permission does not preclude an assertion of fair use.
Is there alternative material I can use that is openly licensed or public domain?
If you decide this is the best route for you, your subject librarian may be able to help find alternative images, etc.
In traditional publishing, authors often transfer some or all of their rights to the publisher as part of the process. Best practice is to negotiate to retain the right to include your work in your thesis or dissertation when you publish. If you did not do that and you want to include a journal article or book chapter you wrote in your thesis or dissertation, you may need to check to be sure your publisher has granted that right to authors (they often do) or you may need to request permission. In some cases, you will need to include a manuscript version of your work rather than the final publisher's version.