Header image shows up HUGE

Hi,
I’m working on this site: http://50.22.11.33/~skymount/
I picked the header image that I wanted for my homepage. When it’s the default image it shows up nice and actual size (239 px x 155 px) in the top left. However when I pick it as the header for just my homepage it shows up huge and centered?
Please help!
Thanks,
Sunny

http://wordpress.org/plugins/wp-display-header/