embedded images in xamarin forms to Button

how to set embedded image to button
I tried this

[ContentProperty("Source")]
public class ImageResourceExtension : IMarkupExtension
{
public string Source { get; set; }

    public object ProvideValue(IServiceProvider serviceProvider)
    {
        if (Source == null) { return null; }
        var imageSource = ImageSource.FromResource(Source);
        return imageSource;
    }
}   

but not working

Thanks,