Support for the WordPress core functionality of a Custom Headers image has been added; and, although this feature is not currently being used here you can easily see it in action at WPFirstAid.com. Also to note, the active theme on WPFirstAid.com is also a Child-Theme of Opus Primus.
The code in place for these Custom Header images is the following:
/** @var $opus_custom_header_support - holds custom header parameters */ $opus_custom_header_support = array( /** * There is no default image in use. * If you were to add one, use %s as a placeholder for the theme * template directory URI. */ 'default-image' => '', /** Support flexible heights. */ 'flex-height' => true, /** Support flexible widths */ 'flex-width' => true, /** Do not support text inside the header image. */ 'header-text' => false, ); /** Add support for Custom Header images */ add_theme_support( 'custom-header', $opus_custom_header_support );
As you can see, there is neither a default image nor default dimensions. The idea is you will use an image appropriate to your site … and in most cases I would recommend this feature be implemented as part of a Child-Theme (and in most of these cases, I would also recommend making the Child-Theme fixed-width).