Background size: 100% does not work on iPhone

Question

I can’t understand why the background size: 100% 100% works in the Safari browser on my desktop and in all iphone emulators online, but not on a real iPhone.

URL of the site http://cherrycompanies.com

CSS I use

#header {
background: url(images/header.png) no-repeat top left;
background-size: 100% 100%;
-webkit-background-size: 100% 100%;
-moz-background-size: 100% 100%;
    -o-background-size: 100% 100%;
margin: auto;

Answer 1

And if you replace background-size: 100% 100%with background-size: contain?