I always give exact sources for my material. This is annoying, boring, and what not. But what is the result? Well, for starters, it means that when a screw-up like this happens, the blog LOOKS much less nice, yes, but all the information on it is still there. Apart from a few "quiz photographs" posts I deliberately gave without sources, all other posts are simply about historical material that I found. So if worse comes to worst, the information is still found, or easily retrieved, by looking at the picture's source.
Update -- solved -- see previous post.