Amp html amp img srcset的问题

我的amp img代码不工作。始终显示来自属性src的图像。谁能告诉我哪里错了

<amp-img src="/v9/public/fileadmin/user_upload/TEST.jpg"
        width="1200"
        height="450"
        layout="responsive"
        alt="alt-text" 
        title="title-text"
        srcset="/v9/public/fileadmin/user_upload/TEST.jpg 998w,
            /v9/public/fileadmin/_processed_/c/b/csm_TEST_ce1818a3d8.jpg 778w,
            /v9/public/fileadmin/_processed_/c/b/csm_TEST_1eee503f4e.jpg 450w"
        sizes="100vw"></amp-img>

我找到了这个解决办法。但是，这会更好

    <amp-img alt="xyz"
             amp-fx="parallax"
             data-parallax-factor="1.2"
             media="(min-width: 832px)"
             width="1200"
             height="450"
             layout="responsive"
             src="<f:uri.image image='{file}' cropVariant='desktop' />"></amp-img>
    <amp-img alt="xyz"
             amp-fx="parallax"
             data-parallax-factor="1.2"
             media="(min-width: 451px) and (max-width: 831px)"
             width="767"
             height="450"
             layout="responsive"
             src="<f:uri.image image='{file}' cropVariant='tablet' />"></amp-img>
    <amp-img alt="xyz"
             amp-fx="parallax"
             data-parallax-factor="1.2"
             media="(min-width: 0px) and (max-width: 450px)"
             width="350"
             height="450"
             layout="responsive"
             src="<f:uri.image image='{file}' cropVariant='mobile' />"></amp-img>