You can search on CC Search for items that have been intentionally licensed by the copyright owner to allow for reuse.
If you're not finding relevant results, try using the old interface by clicking the link in the upper right corner of the page. You should see something like the image below. Select the collection you want to search. For images, I suggest Google Images, Wikimedia Commons, or Europeana. Then make sure to pay attention to the two checked boxes beneath the search bar. If you're not planning to alter the content and you're not using it for commercial purposes, uncheck these boxes. Enter your keywords in the search box and click "search" or press enter. This applies a filter to your search so that you are only searching images with a license that allows them to be reused for your intended purpose.
Fair Use is an exception to copyright law and it should only be relied upon after all efforts to secure permission have been exhausted and under very specific circumstances, in consultation with a librarian. "In its most general sense, a fair use is any copying of copyrighted material done for a limited and “transformative” purpose, such as to comment upon, criticize, or parody a copyrighted work. Such uses can be done without permission from the copyright owner. In other words, fair use is a defense against a claim of copyright infringement. If your use qualifies as a fair use, then it would not be considered an infringement." - https://fairuse.stanford.edu/overview/fair-use/what-is-fair-use/
These are the four factors that judges use to weigh fair use cases:
If you have something else that you want to reuse by, for example, posting on a website or publishing in a book, make sure to contact the copyright holder to seek permission. Document all communications with the copyright holder. To determine who to contact, please refer to the "Basic Copyright Assessments" tab in this Libguide.
In the case of a paper published by multiple authors, they share the copyright. In order to publish that item or even a new edition of that item, for example, you'd need to secure permission from all of the contributors.
If you are examining a photograph that portrays a staged scene in a play, that photograph might have a lighting designer's work, a set designer's work, and a director's work all on display in addition to the photographer's work. In this case, the photographer is the owner of the work - the photograph - that you want to reuse. If you wanted to reproduce the set, you'd need to contact the set designer; if you wanted to reproduce the lighting, the lighting designer, etc.