A friend asked me who was the photo on the header of my emails. There is no photo on my email header. He sent me a screen shot and there is a photo of a lady; I have no idea who it might be or how it got there. He said it started about 6 months ago. Nobody else has reported this. I sent an email to myself and there is nothing. I went through all the settings and found no way to insert a photo. I really need to get this resolved.
Maybe it is being attached by his email client somehow. Is he able to open the email header and show the text string which contains the image? It might show the origin.
What email provider and/or client is he using? What type of device? If he's using a mobile device, maybe it's pulling an image from his contacts.
These articles explain other possibilites.