Thunderbird 17.0.7 on Fedora Linux
I have the Enigmail plugin installed. Whenever I open a message that was GPG signed by someone whose GPG key includes an image, Thunderbird automatically pops up a new eog
application to display the image.
How can I tell Thunderbird/Enigmail not to do this by default?
Open the file ~/.gnupg/gpg.conf
and make sure the following entries are commented out:
list-options show-photos
verify-options show-photos
I think the last one is actually what you're searching for. Do note that this setting has nothing to do with Thunderbird/Enigmail, it will change the default behavior system wide.