This is what the servers at PBase respond when the image is displayed inside the page:
HTTP/1.1 403 Forbidden
Date: Sat, 11 Dec 2010 12:08:15 GMT
Server: Apache/2.0.58 (Unix)
Content-Length: 324
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Content-Type: text/html; charset=iso-8859-1
Seems like hotlinking is not allowed.