I have a photo on my CV. However, it is a headshot only, with a a gentle smile, subtle make-up and smart clothing. I am not sure whether it supports my application or not, but it fits in well with the style of my CV and it is my choice to include it.
Some people prefer not to attach a photo of themselves for whatever reason and I think it is perfectly acceptable whatever the decision. A photo can create bias or discrimination.
If adding a photo, do NOT show cleavage, have alcohol, cigarettes or illegal drugs in your hand, and PLEASE do not wear freaky face paint or spray your hair pink. Most employers would just cast your CV aside at a first glance.