There are a lot of ways you can incorporate images, videos, and even music into your videos without violating anyone’s copyright. You could use your own content, content in the public domain, content available through Creative Commons, or content that is someone else’s but your use is fair use.

In general, a creative work like a photograph is owned by the creator of the work, even if they are a student journalist. However, the school might have some rights to use a student journalist's photos, especially if they signed an agreement.