Why would someone want a picture of them to be on the web at all? I don’t understand the whole idea. What are you trying to show off and to whom? Why should everyone see what you look like? It’s just a guf.
Secular society influences us too much.
I actually believe the couples holding hands SHOULD be on those simcha sites. If there are not shomer negiah than obviously posting on their social media is probably a daily occurrence. While the pictures of so called “frummer” couples wouldn’t be on the web in the first place if they are so “frum”.
I uderstand pictures may get up there by other people but why is that happening? Make sure to tell everyone before that there are no pictures being posted online. Perhaps put up a sign outside the girls house that everyone can see while they walk in for the l’chaim. If you really care about something you’ll put up some sort of barrier.
Also, it’s illegal to put pictures up of someone that were taken in a private area (your own house) when there are signs or you have verbally told the people there not to do so.