We may have solved the mystery why Outlook email signature images are replaced by a Red X. Thanks to a valuable input from Joe Minarik, our unofficial IT guru.
I have been battling this problem for a while. I temporarily solved the problem by recreating my email signature multiple times. But the solution was temporary and required time, always at the wrong time.
I searched for help on the subject. Perhaps I used the wrong search string or just did not dig deep enough in the Google results. It is hard to force yourself to go past the first results page. This is where Joe came to the rescue. He did find something about this mystery earlier. He thinks it was on the 57th search page. (He was persistent.) I would have given up much sooner than that.
Apparently Outlook saves multiple versions of the email images in the temporary internet files folder. Each time the file is saved, the name is indexed such as image001 (1), then image001 (2). When it reaches some magic number, believed to be 99, it can no longer index the files. Then it simply replaces the image with the infamous Red X.
What's the Fix?
It involves some daring. You must open and navigate the machine registry to find the folder containing all the temporary internet files.
1. Open the registry by going to Start button, select Run, enter "regedit" then click OK
2. Navigate the Registry tree in the left pane to locate the following. Substitute your latest version of Office for the "11.0" shown in the path below.
3. Find the folder path shown in OutlookSecureTempFolder registry key (See below). This folder will have a unique name and location for each machine.
4. Right-click the registry key name and select Modify. Copy the folder path and click Cancel.
5. Right-click the Start button and select Explore. Paste the folder path into the address bar and hit Enter. The window will open the Temporary Internet Files folder.
6. Delete the entire contents of the Temporary Internet Files folder.
7. Create a shortcut to the folder location and put it where you can find it. Then you can skip navigating the registry when emptying the folder in the future.
Read more at http://support.microsoft.com/kb/817878. Retaining temporary files in the SecureTempFolder is a known problem. There is no automatic deletion option that I have found. Manual deletion is easy, but takes some effort to remember.
My temporary folder had nearly 4,000 files taking up nearly 650 MB of disc space. There were many image files indexed into the 90s. After emptying the folder, Outlook is keeping the email images intact, at least for the moment.
I'll keep my fingers crossed and planning to empty the temporary folder regularly.