1. Adding a google adsense below your header.


Edit template.html and locate the line {ADMIN_MENU} after that line you can have your 728×90 google adsense

{ADMIN_MENU}
adsense code here

sample page http://kolongo.dpjonline.com

2. Beside the image preview

Open and edit themes.inc.php located at /include/ folder of the coppermine directory.
locate the line {IMAGE}

GOOGLE ADSENSE CODE
{IMAGE}
GOOGLE ADSENSE CODE

sample page http://kolongo.dpjonline.com

Happy Coding !