A TimThumb error has occured

The following error(s) occured:

You may not fetch images from that site. To enable this site in timthumb, you can either add it to $ALLOWED_SITES and set ALLOW_EXTERNAL=true. Or you can set ALLOW_ALL_EXTERNAL_SITES=true, depending on your security needs.

Query String : src=http://imediapixel.com/demo/efolio/wp-content/uploads/2011/12/1133242609-4739.jpg&h=260&w=370&zc=1
TimThumb version : 2.8.10