If this switch is changed from 'Off (2 photos)' to 'On (3 photos)' after photos are already uploaded, an error:
"PHP Error
filesize(): stat failed for /var/www/html/fcms/uploads/photos/member*/full_xx.jpg"
whenever a previously uploaded photo is selected for viewing.
It looks like once the switch is set to "On" it expects that all photos will have a "full_xx.jpg" file. Unfortunately these files do not exist for photos uploaded to the server when the switch was set to "Off".