I was just noticing, all of the "old" PGC emoticons (like Louie and Casey, and the regular emoticons) are typed out :image; while the "new" ones (since Faust) go :image:
Do you see the difference? One ends in a colon, while the other ends in a semicolon.
I don't suppose anyone wants to fix them so they all work the same way? I'd vote for the newer "colon on both ends" way, since it's more simplified.