Classifieds Security Image not showing on Contact User

Hi Support,

In my site, The security image not showing on Contact user. You can see in the screenshot below.
But the image was shown when I login as Administrator User.
When I logged in as Non-Administrator user, the security image is not showing.
After checking with Firebug, there's a "Failed to Load resource" in

Please help me to fix this issue.

Best Regards