Click the Quote button to view this message in a quote, and you will see the image bbcode in this message.
Note: the image has to be available somewhere on the web (in my case, I'm using my ISP's user web space to host the image; some image hosting sites allow you to include your images on other boards, some don't).
This is usually on my head when I am in public:
And these on my feet (image from a marketing site):
Sometimes you can include images from other places. For example, I am currently watching this: