I am thinking that could be a bug or maybe not if block 3 is for the registration. Did you try a different block? I guess sitewide really means sitewide.
That is correct as some apps have their own folder for images. But, I would assume you know what images you want to transfer like profile image, cover image, etc. I did this once just to make all profile and cover images look the same and have the users upload new ones. Moving to a new system is a very expensive endeavor to transfer everything.
Depending on the group's privacy setting people join a group. If you are the owner of the group then you can manage the group and in the settings, there is a tab called invite.
