A more apt comparison is downloading an image that is still under Copyright (Mona Lisa is public domain, though photos of it may not be), getting a high quality print made at a local print shop, hanging it in your living room, and charging people $5 to come look at it.

In this example, there is a tangible personal gain from violating the intellectual property rights of somebody else.

It ain't theft, true, but it ain't a legal business model.