Dutch Rijksmuseum in Amsterdam: Free high Res DL of entire collection
https://www.rijksmuseum.nl/en/search/objecten?js=1&p=8&ps=12&f.publish.apiCollection=XL100#/SK-A-2344,85The Dutch Rijksmuseum just opened up their artwork to the internet. Feel free to download the high res pictures. (Example: Milkmaid by Vermeer).