The background image of the home page, when seen with iPad or iPhone is "cutted", is sense that you can see only a very small top/centered part of it...
I tried to modifiy the template.css in cluding the underlined part in this way:

#jf-slideshow {
background-clip: border-box;
background-color: #00446D;
background-image: url(../images/banner.jpg);
background-origin: padding-box;
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-attachment: fixed;
position: relative;
z-index:50;
}

but it doesn't work, always the same.
Any idea?

Thanks in advance!!!

background-size: 100%; ?

With background-size: 100% the image is deformed...

I've found a partially well satifying answer in the discussion titled "MOBILE BROWSER AND BANNER.JPG"
Thank you very much to Matt!!!