You would not have this issue if you where running any other forum except vb
or invisionboard both of which thing London is the center of the universe.
They are the only applications that I know of that center there time around GMT. Most timestamps come from the server time and then users set a time offset in there profile to make things display right for them. Not them.
Luckily we have a setting for this in your photopost admin global options called gmt offset. You have to place a positive or negative number in it to bring your time back to gmt time not server time and work like vb
say for instance my server for my site is located in central time us. The time there is -6 hours from GMT. Therefore you place a 6 in there which would add that time back to your time and bring it back to 0 or gmt time. If say your located in Poland or say somewhere the server is +2 hours from GMT you would place a -2 in there.