I guess you don't understand me
Changing the offset in constants.php does effect only on the dates created by 4images, i.e. the "added by" date of the images or the post time of comments.
The date on the left side is only an example how to use php code in the templates. This is an direct php output and has nothing to do with 4images.
You have to change the php code directly in the templates, i.e. in home.html
Change
<?php
echo date("d.m.Y, H:i");
?>
to
<?php
echo date("d.m.Y, H:i", time() + (3600 * <time_offset>));
?>
Change <time_offset> to the same value you have set in constants.php
Jan