Expected Behavior

Running validator https://validator.w3.org on basic <picture> elements as per setup config should not result in errors.

Current Behavior

Currently when running validator on:

<picture class="lozad" style="display: block; min-height: 1rem" data-iesrc="images/thumbs/04.jpg" data-alt="">
    <source srcset="images/thumbs/04.jpg" media="(min-width: 1280px)">
   

SVG will very likely take a little longer to render than a base64-encoded raster image. And the Gaussian Blur applied to the simple SVG shapes created by Primitive is probably quite CPU intensive.

Let's run a series of performance tests, ideally on WPT, to compare LQIP raster image rendering performance vs. SQIP rendering performance and also compare CPU utilization.

The value of allowed undershoot in the resize mode ExactOrSmaller is currently a compile time constant. It would be great to make this configurable for the developer using the library:

https://github.com/facebookincubator/spectrum/blob/fa9e917f5b062797d51c3e013aaa7d61926c72a5/cpp/spectrum/core/ResizeUtil.h#L22-L27

您好：
如题，目前文档中缺乏对.env.example重要性的说明。如果在安装前删除了.env.example或者移动安装包内文件到网站根目录时忘记移动.env.examle（由于.env.examle是隐藏文件，默认的mv指令不会移动前者），会导致安装第四步无法写配置文件而报500错误。

此致