Does anyone know what can cause positive camber in the front tires?

I've owned the car for a while now and I noticed the right front tire had some positive camber when i bought it but it didnt look really bad. Now I've decided since the outside wear on the tire is pretty noticable, I want to try to fix it. The alignment is good so i dont think anything is bent... The suspension is stock so does anyone know what might need to be replaced to get my camber back to normal.

A friend of mine said it could be the upper ball joint...

any help would be appreciated!

 

anyone?

 

maybe this can spark some thought... what part of the front suspension deals with camber? Like with camber kits. Is it the ball joint?