I want to put posters of old paintings on my wall - however, to get them at plausible sizes and a DPI that is inoffensive to the eyes, I need big scans (like 8000x8000 px). Despite the fact that these paintings are very old, scans of this quality are wildly difficult to find, often capping out at ~3000x3000, which only amounts to ~12x12 inches at 250 dpi. I was wondering if there are some means of finding high-quality scans that I'm not privy to - I've tried image searches and poking around various museum/government archives with little luck.
I'm particularly interested in picrel, Titian's "Flaying of Marsyas" - this photo is the highest resolution I could find, and has some fucky lighting issues, so I wouldn't like to print it. If anyone has any advice, I'd be happy to receive it :)