Well, if she's padding her boobs, I can see that she wouldn't want that information becoming public, but as the sister comment alluded to, it could just be a baseless accusation without some form of evidence.
Also, seeing a picture of something is completely different than hearing a description. I assume you probably visit the bathroom a few times a day. I have a reasonable idea what you do in there and I could form a decent description of what you do, but you would be upset if someone showed me a picture wouldn't you? Also, you might have a desire to share that moment with some specific people (maybe you're into that kind of thing), but the idea that the person with whom you choose to share that moment has to be balanced by the probability of them taking pictures or videos and sharing it with people you might not even know. Having to make that kind of judgement will limit the number of those moments that will happen, which makes life just a little less fun.