How to get gridview with variable sized gridview items?

I saw that, but it work on the basis of colspan & rowspan. I need to deal with image's height & width. I tried this code it's not working.

 protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
 {
     BindingOperations.SetBinding(element, WidthProperty, new Binding { Path = new PropertyPath("imgWidth") });
     BindingOperations.SetBinding(element, HeightProperty, new Binding { Path = new PropertyPath("imgHeight") });

     base.PrepareContainerForItemOverride(element, item);
 }