If you have a PGP key with a photo included as a UID, you can configure PGP to open it. Out of the box, this will open a preview window, but with iTerm2 you can inline images into your console. The easiest way to do this is
brew tap eddieantonio/eddieantonio brew install imgcat
Then in your
~/.gnupg/gpg.conf file, add the line
photo-viewer "imgcat %i"