- One photo posted every day. - The date and time of each post corresponds to when the picture was taken. - The photos don't have to be posted on the same day it was taken. - Similar photos (or photos of the same thing) taken on different days are allowed. - Photos can't be taken using the 'automatic' setting. Ie. Aperature and shutter speed must be set manually. - Any camera can be used. - Only color balance and contrast / brightness can be corrected.