Jimmy (Jimbo) Wales wrote:
The simple solution is that we need to find as many nicely printed art books from the PD era, and do some mass scanning and uploading, documenting carefully the sources.
We could also encourage some in-person photography by Wikipedians. Some galleries have obnoxious no-photograph rules, but many, especially those owned by governments with some interest in freedom, don't. To just take two examples from my recent travels, the National Archaeological Museum in Athens and the Prado in Madrid both permit no-flash photography. The main trick is how to get high-quality photographs of paintings without a flash, since both do prohibit tripods. But we can at least start tackling some of them: photographs of statues and other artifacts are an easier no-flash/no-tripod target.
-Mark