You can tell an awful lot about someone from how they present themselves in a photo, particularly if you know how to "read" the photo. We insisted on them (as most airlines do these days), as they are a very useful screening tool.
I don't know of any airline that asks for a photo other than a photo copy of your driver's license and passport.
It was suggested in a recruiting book I read years ago that photo's on resumes were a big no no unless it was the industry norm (apparently for actors it's common) The book argued that (especially for girls) it sent out the wrong message and you might get ruled out by how you looked. Also girls might get ruled out too by actually looking too good. If you're some cracking sort 22 year old and the bosses wife is screening the resumes she might just accidentally lose your resume as you are seen as a threat. It was also suggested in the book that people are cynical about people who post up their photos. They were suggesting that the perception of people who put photos on resumes were trying to make up for a lack of ability.