You would first need to figure out the exact size of your image (assuming you’re uploading an image instead of the default logo text). Then change the code in your functions file to the size of your logo. It should look like this –
// Add support for custom header add_theme_support( 'genesis-custom-header', array( 'width' => 360, 'height' => 164 ) );
Then you can upload it in the WordPress Header uploader without needing to crop it.