[Solved]: how to modify the full size popup page?

[Fed]

Hello guys, I'm using coppermine and would like to modify the displayimage.php page to display a banner in the full size popup you get when you click the medium size image

to make it clear, here's a midsize image http://www.imagetemple.com/gallery/displayimage.php?album=18&pos=6, when you click it you get the full size one, that's the page I want to modify

both the pages are displayimage.php so there must be some condition that identifies the popup etc...where would I edit this file to add a banner?

thank you guys

[Nibbler]

Copy theme_display_fullsize_pic() from the sample theme into your custom theme.php and modify your copy.

[Fed]

Copy theme_display_fullsize_pic() from the sample theme into your custom theme.php and modify your copy.

great, thank you