If I'm understanding you correctly, you want to resize a certain theme element, see:
Resizing ThemesPlease edit/update your post if there's something else you're asking, otherwise it'll get locked since we already have a guide for resizing theme elements.
[Definitely, not a feature request]
Update: Tagged title, unlocked topic. This old thread started as a feature request. Fassl clarified about the kernel graphic. OP: if it's something else you're asking, let us know.