A user at one of my clients ran into this today. He couldn’t open any images that were attached to Outlook. (Outlook 2003) Â I first just cleared out any temp files in c:\Users\%USERPROFILE%\AppData\Temp folder and reset it to NOT be read only. Also reset all perms in that folder and subdirs.
Then I went to Internet Explorer settings and Reset all settings and cleared out the cache.
Lastly, I found the Microsoft article below, which speaks about the OutlookSecureTempFolder in the registry and they now supply a “Fixit” option.  I just ran that an then his images would open normally!
http://support.microsoft.com/kb/305982/en-US
FYI: This was on Windows 7 Pro, IE11, Outlook 2003.