How do I get parallax images to scale down on iPad and iPhones?

Greetings professionals,

I'm sort of teaching myself responsive web design and recently redesigned a site for a client using a parallax effect. Works just fine, with the exception of Apple iPads and iPhones. Here is a link to the site. Still working things out with the client, so please don't judge too harshly. Madtown Window Cleaning, LLC

I understand the actual scrolling effect might not work on iPhones or even iPads, but for some reason the background image itself doesn't seem to be scaling down properly as it does on Android.

Anyone here know the secret to getting the background image to display properly?

Thanks for any guidance,

Dave