hmm.....
it really wouldn't matter what the time it is at a certain user's place - just
x+ days from time of upload.
So, as I understand it, an Admin could add an image like normal (this would be an Admin job only, where images can only be added - or images in
certain categories could be added - only by an Admin. Otherwise, users would wonder "where's my image?")
An extra box in the Admin panel, near "Activate Image" could have a box telling the db to "activate the image in xxx days" - 3 days, 10 days, 160 days - whatever. It could be subroutine of the activate function.
....but I'm not gonna code it....