Fix posting images

- since we return the new post html now, we need the Post class to
  not try and decode files as json, since we're not loading that class
  from the db anymore.

inc/display.php

@@ -395,8 +395,10 @@ class Post extends PostProps {
             $this->$key = $value;
         }
 
-        if (isset($this->files) && $this->files)
+        if (isset($this->files) && $this->files
+                && is_string($this->files)) {
             $this->files = @json_decode($this->files);
+        }
         
         $this->subject = utf8tohtml($this->subject);
         $this->name = utf8tohtml($this->name);