I just went through this. Try this.
Step 1 - Set your email to HTML
To do this, click on TOOLS, OPTIONS, MAIL FORMAT
Step 2:
Select HTML. Next make sure you deselect the “use MSOffice word 2003 to
edit e-mail messages†and the one below it. That will ensure that your
messages are sent in HTML only.
Step 3:
Now at the bottom of that same Mail Format window you will see your
signature area. Click on the ‘signatures’ button.
Step 4:
Click on the ‘new’ button.
Step 5:
Enter a name for your Signature and make sure you have the ‘start with blank
signature’ with a bullet in it. Then click the next button.
Step 6:
At this stage you can enter any text you would like as a permanent part of
the signature.Then click on the ‘ADVANCED EDIT’ button.
Step 7:
A popup window will ask for you next move. Click the yes button. At this
point, Microsoft Word should open.
Step 8:
Now you can click on INSERT, PICTURE, FROM FILE. Go to your Desktop to
locate the GIF file or link and double-click the file. ***Please note: It
will now appear on your page - not be animated.
Step 9:
Go to FILE and SAVE AS (The file will probably save in what is called a
"Signature" folder.)
Step 10:
In your toolbar along the bottom of your computer screen, click on
"OUTLOOK". The dialog box for Signatures should re-appear and you should see
the animated graphic in the preview box.
Step 11:
Click OK
Step 12:
In the "Signature for New Messages" box, click the drop down menu and select
your signature (or whatever the name of the file you designated).
Step 13:
Click APPLY and OK
Step 14:
Open up a new email message and, at this point, the animated graphic will
appear! You may need to click on it (only once to highlight it)