You need to upload the image to another place on the internet. There are hosts available which allow you to upload a single file, for the sole purpouse of using it in a signature on forums (I believe Kao does at
http://www.kaonet.net).
Then, go to your user cp, click edit signature and use the code [img]url[/img] with url being the address of the image (location you hosted it on).
Those 'stickers' were in reply to the Translator and Official Tester images. Chris Boulton made them, but I'm not sure if he's still handing them out.
The forum you posted in, Help & Support, is only for problems related to the Messenger Plus! program. I reported this thread; it will be moved when a moderator comes online
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