MSM Sitemap customization

gistfile1.txt

<?php 

function vip_customize_msm_sitemap_entry( $url ) {
    if ( $url instanceof SimpleXMLElement ) {

        // Add images to the sitemap entry.
        $post_id = get_the_ID();
        $thumbnail_id = get_post_thumbnail_id( $post_id );

        if ( $thumbnail_id ) {
			// Get the URL of the featured image.
			$image_url = wp_get_attachment_url( $thumbnail_id );
			if ( $image_url ) {
				// Add the <image:image> tag with the featured image.
				$image_tag = $url->addChild( 'image:image' );
				$image_tag->addChild( 'image:loc', esc_url( $image_url ) );

				// Optionally add the image title.
				$image_title = get_the_title( $thumbnail_id );
				if ( $image_title ) {
					$image_tag->addChild( 'image:title', esc_html( $image_title ) );
				}
			}
		}

        // Remove the changefreq element.
        if ( isset( $url->changefreq ) ) {
            unset( $url->changefreq[0] );
        }
    
        // Remove the priority element.
        if ( isset( $url->priority ) ) {
            unset( $url->priority[0] );
        }
    }
    
    return $url;
}
    
    add_filter( 'msm_sitemap_entry', 'vip_customize_msm_sitemap_entry', 10, 1 );