I have gotten into postcrossing, and yesterday i have received a postcard from a person in Turkey, and i quickly noticed that the photo of him that he used on his profile was on one of the stamps. I was, of course, quite interested and wrote to him asking about that. Apparently Turkey has the service that they call PS (Personal Stamp), or at least that's how he translated it into english, and you are allowed to create a personalised stamps and explicitly permitted to use your photos.
Thus if you live in Turkey you can have yourself on a stamp... in fact now i visit Turkey every so often, and i will try to find out if a process is quick enough for me to make the stamps of myself made as well. Not to send out, but as a collectible q;-)=
P.S. I believe that we should make some sort of note on this project saying that only people who had the official, distributed to the wider public stamps designed by or for the post office of whatever country are eligible to be added here, lest we have a flood where everybody is on a stamp.
http://mentalfloss.com/article/24349/how-get-yourself-postage-stamp
https://www.usps.com/ship/custom-mail-stamps.htm
How about that, it's legal stamping in the US.
The term is "no personlised stamps" perhaps?