I don't find the photo particularly scandalous, but taken in the context of the tech industry issues with sexism, it definitely shows a lack of awareness on the part of the organizers.

I would hate to see us become so politically correct that we can't show a picture of people having fun to advertise a party. But, it's not that hard to find stock images of both men and women who are attractive, having fun together and not dressed up like playboy models kissing one another.