I produce book for Standard Ebooks, and they need cover art.[1] Arts & Culture is a good source, but I also use Wikimedia Commons and some museum sites directly

I produce book for Standard Ebooks, and they need cover art.[1] Arts & Culture is a good source, but I also use Wikimedia Commons and some museum sites directly. [1] https://standardebooks.org/artworks https://standardebooks.org/artworks