Setting background for every page in Xamarin forms

Hi ,

I would like to set the background image for every page and it should be accessible for every where .I have seen and got some information about how to do it in the net from the following link

https://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/styles/

var buttonStyle = new Style (typeof(Button)) {
    Setters = {
        new Setter {Property = Button.BackgroundColorProperty, Value = Color.Yellow},
        new Setter {Property = Button.BorderRadiusProperty, Value = 0},
        new Setter {Property = Button.HeightRequestProperty, Value = 42}
    }
}
// apply directly to a single control
var mybutton = new Button {
    Text = "Style Me",
    Style = buttonStyle
};

similarly I would like to use for image how can I do that.

Any one got answer for this?????