Website display on iPhone uses a picture that isn't on the website. How and why did that happen?

A recently launched website appears on iPhones iOS 4 and 5) displaying a picture that isn't on the website and has little to do with the business. How and why did that happen? How can we correct that?

NOTE: The site was designed for standard and mobile platforms and appears correctly on on an Android. It also appears correctly using Safari, IE, Firefox or various Windows browers. One laptop using Windows Vista didn't correctly display some of the drop-down menus.