gistfile1.txt

Locate this code in wp-content/plugins/wordpress-seo/inc/class-sitemaps.php, around line 362:

  			$content = $p->post_content;
				if ( function_exists( 'get_the_post_thumbnail' ) ) {
					$content = '<p>' . get_the_post_thumbnail( $p->ID, 'full' ) . '</p>' . $content;
				}

After that code snippet, insert this additional code:

                // MODIFICATION: ENABLE EASYROTATOR IMAGE COMPATIBILITY
                if (stripos($content, '[easyrotator') !== false)
                {
                    $content = do_shortcode($content);
                    $content = preg_replace('|<img class="thumb" src=".*? />|i', '', $content);
                }
                // END MODIFICATION

Then save the file.