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I do not remember if that picture is associated with your user account or your Address Book. Test both.

To remove picture for User Account:
System Preferences > Accounts > Select Picture to change

To remove picture from Address Book:
Applications > Address Book.app > Find yourself

Again, I'm sorry can't remember which one it is, but do both and test accordingly!
 
I do not remember if that picture is associated with your user account or your Address Book. Test both.

To remove picture for User Account:
System Preferences > Accounts > Select Picture to change

To remove picture from Address Book:
Applications > Address Book.app > Find yourself

Again, I'm sorry can't remember which one it is, but do both and test accordingly!

I would think it's in the signature portion of the Mail app. Not on my Mac to point out exactly where in Mail it is.

Edit: Like he said.
VVVVVVVVVVVVV
 
Dude

It might just show your Mac account pic... On your email, not sending it out... Check at before you start to freak.

Trust me the whole world isn't getting your rubber froggy pic.

Can www check out your cheesy mug?
 
The account picture is not used. If you use Mail it will use the address cards from address book to display additional information like pictures. This is only a clientside setting, it does not send out any information to others. In address book you can add your own address card and define it as "my card" (in address book go to the menubar and choose Card > Make This My Card). I think you might have done something like that, probably when you got the Mac and filled out all of the fields when you were setting up your user account (which is skippable if by being very persistent in saying no). Delete your address card or picture from your address card and it will stop displaying your picture.

If the picture is shown in the body of the mail (the area where you type your message) it probably is some signature with your picture in it. If so do what miles01110 tells you.
 
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