Use Photo Booth in the room's creation tools to take a picture. The photo appears in the room as a small polaroid with the room's name and date.
Download the picture
The person taking the photo gets the full-size picture downloaded. Anyone in the room can open the polaroid's menu and choose Download photo.
Can I copy or restore a photo?
Polaroids cannot be duplicated, and they are not carried over when a room is copied. Trashing a polaroid deletes its photo permanently, so Undo cannot restore it. Download a copy first if you want to keep it.