Right now, the tweet is fixed.
Why can't I change it?
Basically, we wanted to create a fun and simple app that we could code up in under 2 weeks. Most of the work went into capturing the photos as well as possible, and we simply ran out of time to add the editing functionality.
We may add this in in a future version.
If you do want to change what gets tweeted, after your photo is taken, you can tweet it from the camera roll on your device, rather than from Triggertrap Selfie itself!