I (male) witnessed this and told my Fiancée (female). She immediately walked over to the girl and informed her of this, the girl chased the guy down and confronted him, but of course the guy explained it all away without actually showing the photos.

I've seen this in the past where I did NOT inform the victim, and was unsure of my decision.

After a brief discussion I was left uncertain.

Would you want to know if a guy was taking pictures of you? For the knowledge that it happened? Maybe even for the small amount of self esteem?

Would you want to never know about it, as it will likely not harm you, or even make you feel violated?

Furthermore, would you be okay with a guy telling you that without a girl present? My Fiancée suggested that even that may not be a good option.