If you are looking for a specific work of art, and you’re not sure what museum holds it, Google Arts and Culture is a good place to start. They have high resolution images (that can be zoomed in) of more than 2000 works. In addition, they have information on those works, as well as articles on specific artists, works, themes, cultures, etc. This is a great resource, and it’s also a fun sight to explore if you have a bit of extra time. Keep in mind that this site is distinct from the regular Google search engine. They also have a helpful app for your phones.