I cannot stand getting anymore those blah-blah invitations :

"Hello you, I'm an admin of the group "Blah-Blah-images". It would be great if you would add this doc to our group. Thank you !"

this means, that the inviting person is not really interested in your pic... he doesn't comment, not even a few words... he just invites as many people as possible for his senseless group, where he brushes up his poor ego as a moderator...

I think this is a bad selfish behaviour without any manners... and in future I will block every person who will send me such a prefabricated blah-blah invitation !!!