// PropertyValueUIHandler delegate that provides PropertyValueUIItem
// objects to any properties named HorizontalMargin or VerticalMargin.
private void marginPropertyValueUIHandler(System.ComponentModel.ITypeDescriptorContext context, System.ComponentModel.PropertyDescriptor propDesc, ArrayList itemList)
{
    // A PropertyValueUIHandler added to the IPropertyValueUIService
    // is queried once for each property of a component and passed
    // a PropertyDescriptor that represents the characteristics of 
    // the property when the Properties window is set to a new 
    // component. A PropertyValueUIHandler can determine whether 
    // to add a PropertyValueUIItem for the object to its ValueUIItem 
    // list depending on the values of the PropertyDescriptor.
    if( propDesc.DisplayName.Equals( "HorizontalMargin" ) )
    {
        Image img = DeserializeFromBase64Text(imageBlob1);
        itemList.Add( new PropertyValueUIItem( img, new PropertyValueUIItemInvokeHandler(this.marginInvoke), "Test ToolTip") );
    }
    if( propDesc.DisplayName.Equals( "VerticalMargin" ) )
    {
        Image img = DeserializeFromBase64Text(imageBlob1);
        img.RotateFlip(RotateFlipType.Rotate90FlipNone);
        itemList.Add( new PropertyValueUIItem( img, new PropertyValueUIItemInvokeHandler(this.marginInvoke), "Test ToolTip") );
    }
}