Thanks! Your post was fascinating, so I think I really would have enjoyed the lecture. I did a study in seminary about the beliefs about demons in the first century, and from what I found, many people believed that they were in everything - from shoes that were wearing out to excrement. No surprise to me that it was believed that they were destroying demons by destroying idols.
There's a passage in Acts about Christians burning a large amount of documents related to magic and no doubt demons as well. (Acts 19:19)I'm guessing if they did that, they were destroying artwork as well, even then.