Musical iconography is concerned with the depiction of music in the visual arts. It is a discipline in its own right, covering the illustration of musicians, instruments, music-making, and the use of musical imagery.
https://images.google.com/
Purports to be "the most comprehensive image search on the web."
JSTOR incorporated the former database, ARTstor, in August 2024. The image component of JSTOR contains nearly one million images in the areas of art, architecture, the humanities, and social sciences for research and pedagogical purposes.
https://mimo-international.com/MIMO/
A database of information about musical instruments held in public collections, containing more than 76,000 images.
https://db.ridim.org/
The RId'IM database contains images and descriptions depicting music-making, musical instruments, and similar related objects. Where possible, there are links to online images of the artwork.