Responsive, high performance images in umbraco 9

Umbraco9Images.cshtml

@* /Views/Partials/ResponsiveImage.cshtml *@
@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage
@using Umbraco.Cms.Core.Media
@using Umbraco.Cms.Core.Models.PublishedContent
@using Umbraco.Cms.Core.Routing

@{

    var publishedContent =  @ViewData["publishedContent"] as IPublishedContent ?? null;
    var lazyLoading =  @ViewData["lazyLoading"] ?? false;
    @* var imageWebP = publishedContent?.GetCropUrl(width: 600, height: 20, quality:80, furtherOptions: "&format=webp") ?? ""; Webp not yet available on SixLabors.ImageSharp*@
    var imageJpeg = publishedContent?.GetCropUrl(width: 600, height: 20, quality:80, furtherOptions: "&format=jpg") ?? "";
    var imageOriginal = publishedContent?.GetCropUrl(600, 20) ?? "";
}

<picture>
	@* <source srcset="@imageWebP" type="image/webp"> *@
	<source srcset="@imageJpeg" type='image/jpeg'>
	<img src="@imageOriginal" width="600" height="20" loading="@lazyLoading" height="20" alt="" />
</picture>