Pics not displaying

When I am logged into this site using my I Pad, I can't see some of the pictures other members post in their comments. All is see is a box outline with IMG_0293.jpg but no picture. If I click in the box where the picture would be, I get a msg with says, Permission denied: links to files in the forum are only allowed from the forum itself? When i use my I Mac, I can see the pictures fine. Any idea why the problem on I pad?