You don't take the Selfie until 24 hours before (at most -- you can wait if you think you might sell it). Until then, there's a simple flow to email the ticket to someone else.
Then the show the photo they just took to the bouncer to get in?
I think the reaction from people at these events will be 'this app is dumb' after seeing someone take a photo then show it to the bouncer when the look exactly the same in real life!
I mean, wouldn't you feel silly if you had bought and paid for a ticket to an event then had to take a photo of yourself standing in line in order to get in?
[Edit: my constructive criticism here is what are you going to do about the users who will take the photo at the last second?]