This is a collaborative wiki but attribution is to be made to the respective producers of the page, particularly if they are the sole authors.
In accordance with Wikimedia policy I consider photos of public domain works of art, including archaeological artifacts, to be public domain themselves. Given Bridgeman Art Library v. Corel Corp. it is my understanding that exact photographic copies of public domain works of art are considered public domain themselves. Law Professor Christopher Sprigman has confirmed this. Nonetheless as a professional courtesy I make reasonable effort to ascertain who the photographer is, providing a link back to the original source site while attributing them as the photographer on the photo's file page.