I noticed when I add a parallax effect to an image, the image gets very big and some of it gets hidden, what am I doing wrong?

[yanayn]

Hi,
In order to create the Parallax effect the image must be bigger so that in can be scrolled slower then the regular page scroll.
When we zoom in on the image and position it on the top in order to create the effect, some of the bottom part must be cut out of the frame.