FlockEye makes several iOS devices to take picture or video at the same time, then it collects those pictures or videos at master and shows you, then if you like you might save them to the photo library.
Open FlockEye on the devices you would like to take picture with. Make sure bluetooth and Wifi is active on those devices. Choose one of devices as master and wait for the connections were established. When you saw red dot touch it to take pictures. But you might want to wait till all the slaves are connected. Now, wait while all the pictures are being received by master and that is it.
A problem is making application unstable if user touch countdown has been removed.