page speed insights doesn't do srcset / sizes (no more)

hglr

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Jan 24, 2017, 7:46:49 AM1/24/17

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hello all,

as far as i searched the group i couldn't find anything on the topic yet ...

since 2-3 weeks google page speed insights seems to choke on srcset & sizes, in that it completely ignores both and only loads the file referenced in the src attribute.

test case:

page with a 50% image container
an image with 5 srcset references
and 1 sizes attribute (50vw)
and a different src attribute to show the failure

<!doctype html>
<html>

<head>
  <meta charset="utf-8">
  <title>Page Speed Insights Test - srcset / sizes</title>
  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
</head>

<style>div{width:50%;margin: 0 auto}img{max-width:100%}</style>

<body>
  <div>
    <img srcset="img-ok-400.png 400w, img-ok-600.png 600w, img-ok-800.png 800w, img-ok-1200.png 1200w, img-ok-1600.png 1600w"
         sizes="50vw"
         src="https://placekitten.com/g/1600/1200">
  </div>
</body>

</html>

local chrome selects the right image from srcset and everything works as expected

but page speed insights always loads the file referenced in the src attribute, seemingly ignoring srcset & sizes completely:

can anyone confirm this?

Rick Steinwand

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Jan 24, 2017, 8:34:26 AM1/24/17

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I can confirm the <picture> element works.

Enrica Ruedin

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Mar 22, 2018, 7:36:42 AM3/22/18

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<pictures> isn't an option for me, because contao as cms generates different picture sizes automatically and it uses "srcset" and "sizes".

Page speed doesn't take the "src" defined image. It chooses any image sometimes with 1500w for mobile! So i get 43% ranking.