I only get x's instead of images when opening emails from certain businesses (Best Buy Redbox Wal-Mart) etc.  I have done some on line research but have found nothing that helps me.  One subject on the internet said to click on the yellow bar at the top of the email that says "show images".  This bar, however does not appear.  I have added these domains to my safe sender list but still doesn't help. My operating system is Windows 7 Professional.  I use the free version of AVG for anti-virus.

Any suggestions?