When you do a passport of visa photo on your own, you need to put your head straight, but this is hard, because you naturally tilt your head or a person who is taking a shot can hold a camera or smartphone not straight. To work around you need to take several shots to make sure that one of them has the head straight. But the problem is that it could have had other glitches (like your eyes can be closed, or hair is a mess, or your mouth is open, and so on).
So in the past to really make sure your head is straight, the eye line is straight, you needed a photoshop software, you needed to be familiar with image processing a little bit to be able to rotate the picture and align your head first before doing anything else with your passport photo.
But it is different these days. Visafoto.com does everything automatically, including fixing head tilt and rotation.
Visafoto.com knows all the passport photo requirements for various countries and does everything automatically in seconds.
So if you have your photo ready, you can convert it to a correct passport or visa photo right now at visafoto.com.