#329: imagesrcset and imagesizes attributes on link rel=preload

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Opened Nov 29, 2018

こんにちはTAG！

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Two issues have been raised in the past discussions:

  • <picture> use-case: It's not always easy or possible to create a set of <link rel=preload>s whose selection logic is equivalent to a <picture> element. This was discussed at TPAC 2018, and a summary is here.

  • Preloads that depend on viewport dimensions would need to be delayed until the end of the <head> tag, where the viewport is locked. (This is not an issue specific to imagesrcset/imagesizes, since preload can have media attribute.) That means most imagesrcsets cannot be preloaded just by preprocessing HTTP headers. We plan to discuss the viewport issue separately from this one.

We'd prefer the TAG provide feedback as (please select one):

  • open issues in our Github repo for each point of feedback
  • open a single issue in our Github repo for the entire review
  • leave review feedback as a comment in this issue

cc: @yoavweiss

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