By default the page header title with background displays the full image selected so you can crop it prior to uploaded if wanted. However, if you want to add a new custom image size for this it is possible via the code below.
// Add new image size setting
add_filter( 'wpex_image_sizes', function( $sizes ) {
$sizes['page_header_bg'] = array(
'label' => __( 'Page Header Bacground', 'wpex' ), // Label
'width' => 'page_header_bg_width', // id for theme_mod width
'height' => 'page_header_bg_height', // id for theme_mod height
'crop' => 'page_header_bg_crop', // id for theme_mod crop
);
return $sizes;
}, 9999 );
// Alter the page header background output
add_filter( 'wpex_page_header_background_image', function( $image ) {
$post_id = get_the_ID();
$attachment_id = get_post_meta( $post_id, 'wpex_post_title_background', true );
$attachment_id = $attachment_id ? $attachment_id : get_post_meta( $post_id, 'wpex_post_title_background_redux', true );
if ( $attachment_id && is_numeric( $attachment_id ) ) {
$image = wpex_get_post_thumbnail_url( array(
'attachment' => $attachment_id,
'size' => 'page_header_bg',
) );
}
return $image;
}, 10 );