The times could be slightly askew because of the difference in clocks. For example, of the three clocks I can see in my kitchen--microwave, stove and kitchen clock on the wall--I can get three different times! Neither of my car clocks are in sync with my watch, and my cell phone clock is different, too!
We're only talking a few minutes, give or take.
I think the timestamps on the cellphone pics would be very accurate, since they come from the cell system....clock settings on digital cams could be off, though