I think it would change my appearance significantly - I've used photoshopped images of myself on dating sites and had a night and day difference in my responses
Just out of interest why do you hold that view though? Are you just saying the changes are so subtle as to be barely noticeable?
I hold that view because I had jaw surgery some months ago with big movements.
Additionally, I have made some friends over at progenica (german jaw surgery board) and asked them frankly about their experiences after their surgery(ies).
You are looking at still pictures made with expensive digital stereo cameras (that's what surgeons use to highlight/accentuate deformities to help with planning). Real life differences will be less obvious, especially because people aren't staying perfectly still in natural head position all the time.
EDIT: The pic you posted has also been tampered with. Look at the background of the before and after - the contrast has been f**ked with to make her before face flatter/blander/rounder/s**ttier overall.
That's not to say that surgery won't improve looks. It just won't improve them enough.
I am just relaying information, not trying to stop you or anything.