Some images not loading

[mafiosa]

I am facing an issue with squid.I have squid and squidguard enabled along with captive portal.The problem is that some images on facebook chat do not load as well as some youtube thumbnails also do not load up.Refreshing the page multiple times does not help.A screen shot is attached.Kindly help me out.

[AR15USR]

Do you have any of the tracking blocks on in squid guard?

[mafiosa]

I only block porn.