The default header image size is 960×100 pixels. There is no option to change through admin options but it’s possible editing some code in the theme files.
While editing the height should not be an issue, using a width of less than 960x may result in some problems. You can test with the procedure below different renderings.
To adjust the logo height, try this:
1. Before you begin, please run a full backup of your website. We will not be able to help if the site has not been backed up entirely.
2. Head to Appearance->Editor and locate the functions.php file and look for
add_theme_support( ‘genesis-custom-header’, array( ‘width’ => 960, ‘height’ => 100, ‘textcolor’ => ‘333’, ‘admin_header_callback’ => ‘sc_admin_style’, ‘header_callback’ => ‘sc_custom_header_style’ ) );
3. Change the height to your desired height in pixel – i.e if your logo is 250px tall change “height” = > 250
4. Then go to the CSS (stylesheet.css) and look for #header #title div (near line number 130)
5. Change line-height: 100px; to the desired height
6. Finally go to the header section and upload your logo