Picture frames

We are having an exhibition in Taiwan this November. We went shopping for picture frames today. But I have a strange hatred for picture frames. If their function is to hold a picture vertically on a wall.... they are doing it in a very inefficient way. I don't see why they have to be so big and heavy. Mankind has been using picture frames before Da Vinci but no one has invented something better? (Blue tack kind of works.) It is hard to explain why I don't like them. But we are still going to use them.