>>2261125Google Art Project has the highest res images available online. You can't download them directly from there though anymore, but there are workarounds to it. And actually wikipedia has all of the images rehosted there too, so you can find it on wikipedia then save them.
The other best place is to look through auction houses that frequently sell art. They often post hi-res images since some people will be spending 10's of thousands on paintings they may not be able to see in real life first.
Lastly, the laziest route is when doing a google image search for an artist you click Search Tools> Size>Large.
