If you have user complaints about their Outlook doesn’t show images, but when you checked all the settings are correct, the hack below might be able to help, at least it works for me.
The story is a network user cannot see images down the signature area, other images are fine. I have checked all the settings, I still couldn’t find any thing that causes this. Then I came across this on TechNet, it took me to a forum http://www.tek-tips.com/viewthread.cfm?qid=1353596
The idea is to remove a registry key for Outlook security, and this registry is pointing to a temp folder, possibly the temp folder corrupted?!
HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security. It contains a key called “OutlookSecureTempFolder “. When I deleted that key, all images began to show.
anyway, it worked for my case, and I hope it will work for you too. (BTW, don’t forget to export the registry before you make any changes!)