help needed for webdev style

[cowabunga]

hi there,

i'm a newbie who has shamelessly copied webdev's (http://www.pbase.com/webdev) most excellent stylesheet onto mine.

however, a problem arises when my images exceed a certain size. the picture is no longer centered.

for large image size


for original image size


so can some1 pls enlighten me on how i'm supposed to fix this problem? any help would be greatly appreciated!