Fixes regarding the new default profile photo size. The default profile photos are just renamed. People which provided the originals are invited to reproduce them in the new 300 by 300 px format.

include/identity.php

@@ -1393,10 +1393,10 @@ function get_theme_uid() {
 * with the specified size.
 *
 * @param int $size
-*  one of (175, 80, 48)
+*  one of (300, 80, 48)
 * @returns string
 */
-function get_default_profile_photo($size = 175) {
+function get_default_profile_photo($size = 300) {
 	$scheme = get_config('system','default_profile_photo');
 	if(! $scheme)
 		$scheme = 'rainbow_man';