heightof site title image

Hi
for our web site we need a title image below the navigation bar appearing on every page.
I used this setting:
highend settings -> layout settings -> default settings -> site title ->
title type: site title with background image
and uploaded an image file.
Now I want to display this image with a bigger than the standard height.
How can I achieve this?

Can I make this image beeing a link?

Thanks in advance
Ibrahim