You can insert your picture in the header of your mail message so that
recipients see your face in the From: header field if their
mail user agent is sophisticated enough. In MH-E, this is done by
placing your image in the file named by the option
mh-x-face-file which is ~/.face by default.
If the file starts with either of the strings X-Face:, Face: or X-Image-URL: then the contents are added to the message header verbatim. Otherwise it is assumed that the file contains the value of the X-Face: header field.
The X-Face: header field, which is a low-resolution, black and white image, can be generated using the compface command. The Online X-Face Converter is a useful resource for quick conversion of images into X-Face: header fields.
Use the make-face script to convert a JPEG image to the higher resolution, color, Face: header field.
The URL of any image can be used for the X-Image-URL: field and no processing of the image is required.
To prevent the setting of any of these header fields, either set
mh-x-face-file to nil, or simply ensure that the file
defined by this option doesn't exist.
See Viewing, to see how these header fields are displayed in MH-E.