a) Changing from a 'Custom' setting (pointing to Thunderbird) under Preferred Applications allowed me to send an email message with a single attached image,
b) Attaching multiple images (19 in total) failed with the message: 'Sending of message failed.
Unable to open the temporary file /tmp/tmp9264968.tmp/P1070377.JPG. Check your 'Temporary Directory' setting.'
More info:
a) Changing from a 'Custom' setting (pointing to Thunderbird) under Preferred Applications allowed me to send an email message with a single attached image,
b) Attaching multiple images (19 in total) failed with the message: 'Sending of message failed. .tmp/P1070377. JPG. Check your 'Temporary Directory' setting.'
Unable to open the temporary file /tmp/tmp9264968
So it sort-of works, but not well enough. *sigh*