API Mark image tracking as owned

code/model/SiteTreeFileExtension.php

@@ -19,6 +19,16 @@ class SiteTreeFileExtension extends DataExtension {
 		'BackLinkTracking' => 'SiteTree.ImageTracking' // {@see SiteTreeLinkTracking}
 	);
 
+	/**
+	 * Images tracked by pages are owned by those pages
+	 *
+	 * @config
+	 * @var array
+	 */
+	private static $owned_by = array(
+		'BackLinkTracking'
+	);
+
 	public function updateCMSFields(FieldList $fields) {
 		$fields->insertAfter(
 			ReadonlyField::create(

code/model/SiteTreeLinkTracking.php

@@ -41,13 +41,23 @@ class SiteTreeLinkTracking extends DataExtension {
 
 	private static $many_many = array(
 		"LinkTracking" => "SiteTree",
-		"ImageTracking" => "File"
+		"ImageTracking" => "File"  // {@see SiteTreeFileExtension}
 	);
 
 	private static $belongs_many_many = array(
 		"BackLinkTracking" => "SiteTree.LinkTracking"
 	);
 
+	/**
+	 * Tracked images are considered owned by this page
+	 *
+	 * @config
+	 * @var array
+	 */
+	private static $owns = array(
+		"ImageTracking"
+	);
+
 	private static $many_many_extraFields = array(
 		"LinkTracking" => array("FieldName" => "Varchar"),
 		"ImageTracking" => array("FieldName" => "Varchar")