Minor adjustments in Pageimage and Pagefile classes

wire/core/Pagefile.php

@@ -368,7 +368,7 @@ class Pagefile extends WireData {
 	 * - To unset, specify boolean false (or null) for $key, and the name of the property to unset as $value. 
 	 * - To unset, you can also get all values, unset it from the retuned array, and set the array back. 
 	 * 
-	 * #pw-internal
+	 * #pw-group-manipulation
 	 * 
 	 * @param string|array|false|null $key Specify array to set all file data, or key (string) to set or get a property,
 	 *  Or specify boolean false to remove key specified by $value argument.

wire/core/Pageimage.php

@@ -977,7 +977,7 @@ class Pageimage extends Pagefile {
 	 * @return Pageimage
 	 *
 	 */
-	public function hidpiSize($width, $height, $options = array()) {
+	public function hidpiSize($width, $height = 0, $options = array()) {
 		if(is_array($height)) {
 			$height['hidpi'] = true;
 		} else {