images not appearing - An Avast problem?

[bad dog]

THE PROBLEM:
Images are not appearing in Firefox - in place of the missing images are generic image placeholders.

BACKGROUND INFORMATION:
For instance, in forums the avatars are missing, as are the embedded photos in the threads. In place of the missing images are generic image placeholders.

I have gone through all of my Firefox security settings.
Cleared the cache and cookies.
Reset Firefox.
Rebooted the computer.
Gone through the Firefox trouble-shooting algorithms, etc.
On another day or another time the problem evaporates.
Other days the images are missing.

MY QUESTION:
Could Avast be blocking the images? I searched the Avast forums and see nothing about blocked images.

MORE INFORMATION:
This might be a clue - when I tried to register for this forum, I kept getting an error that my typed letters did not match the verification image.
But there was no verification image!!
I refreshed the browser over and over - but there was no verification line and no verification image, either.
Finally after refreshing about a dozen times, a verification line/image appeared and I was able to register.
Could this be related or a clue as to what is happening?

Please don't tell me to use IE.

MY SYSTEM:
Windows 7
32 bit
Firefox 19.0.02
Avast Pro

[Pondus]

I have gone through all of my Firefox security settings, the Firefox trouble-shooting algorithms, etc. Could Avast be blocking the images? I searched the Avast forums and see nothing about blocked images.

if you right click avast tray icon....and pause shields for xx minutes..... does it work then ?

[bad dog]

Disabled Avast x 10 min

Images appear!

I guess that means that it's an Avast problem.

Now what? I can't leave Avast disabled forever.

And what about the problem of the missing verification image when i tried to register for this forum? Was Avast blocking that too? (:

[Pondus]

try again...this time only webshield?