Dave: You can test that your photo gets to the Rally email address as much as you like before the rally, and as soon as I see them I will respond (please note, not monitored 24/7). This hopefully will give you the confidence that the system works and that your photography skills are improving. On the rally itself you will not get confirmation for every photo that you send.
Wouldn't putting an out of office auto reply be simpler? This would then confirm receipt within a minute, and confirm receipt for every photo