I suddenly get a red X instead of graphics/pictures on certain web pages (ebay and RV.NET). I recently installed ZoneAlarm Pro so this could be the issue. I tried to find an answer on ZA web site, but didn't find anything. Any help will be appreciated.

I have a Dell DIM4600 running Win XL Home with plenty of memory and storage.

BAD

Check your settings in ZA privacy. The main window should have medium ad blocking and mobile control code off.
Which version of ZAPro are you using? Some of the later ones are known to cause problems.