Method #1: Search the USIC databases and sources simultaneously using a Discovery Search. Good for finding images on research topics.

Method #2: Search in a subject-specific database. Good for finding a specific art image, a specific documentary, or specific piece of music.
Images: Art Museum Image Gallery
Images: Grove Art Online
Videos: Kanopy Documentaries
Videos: Alexander Street
Videos: Safari Montage
Music: Naxos Music Library
Music: Naxos Jazz
Method #3: Search a Licensed Image, Video, or Music Site. Good for finding backgrounds, icons, brief clips, etc. for inserting into projects in many different formats. There are many, but here are a few places to begin.
Images: Search on the Creative Commons (CC). CC images are open-source and licensed for usage with copyright permissions. To learn more about Creative Commons and licensing images, see their FAQs.