I don’t think it’s about having the property. Whether someone would take pictures of it or not, they still have their body as “property”. If it were to be stolen then perhaps the metaphor would be that someone assaulted them or took the images themselves.

The grey area is voluntarily taking the images and storing them in an insecure way, or sending them in a way that could be compromised or to numerous or questionable people. Taking the images and the risk of it all is thrilling for many people, but they don’t always consider why it feels that way, and how it could go badly.

How the images are handled is a large factor in responsibility. If they are handled very well, then they have minimal responsibility. If they have sent them to multiple people over the years, it’s highly likely they will end up somewhere, especially as romantic obligation fades and people will become careless over time.

My belief is taking the images is probably not a good idea, but if you must, make sure your security is tight, but don’t be totally surprised if something happens.