A while ago I saw this image on Historical LOLs and decided to track it down:
It’s called “Picture Gallery with Views of Modern Rome”, painted by Giovanni Paolo Pannini around 1757. The whole thing looks like this:
Several months later, I found out about a similar series of paintings created about eighty years earlier documenting the super-huge art collection of Archduke Leopold of Austria. From 1639 to 1653, David Teniers the Younger created eight paintings like this. Too bad photography hadn’t been invented yet – it would have been soooo much easier that way!
Teniers did it so well that many of the depicted artworks are easily identifiable, as you can see here (you can click on them!). You can see the whole series by clicking “Archduke Leopold in his Gallery at Brussels” on the wikipaintings page.