Here's a quick guide on how to lock and unlock all the infographics that group members create.
Next you want to select "On" from the next screen. Selecting "On" will set everyones infographic within the group to "Public". Public will allow everyone see a members infographic.
Selecting "Off" will set all the infographics to "Private" - Private means that nobody can see them.
Note: If you find that a users infographic is locked still, you need to hit the "On" button again and it will open up again.