[wp-trac] [WordPress Trac] #55443: Create WebP sub-sizes and use for output

[WordPress Trac]

#55443: Create WebP sub-sizes and use for output
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 Reporter:  adamsilverstein                      |       Owner:
                                                 |  adamsilverstein
     Type:  enhancement                          |      Status:  assigned
 Priority:  normal                               |   Milestone:  6.1
Component:  Media                                |     Version:  6.0
 Severity:  normal                               |  Resolution:
 Keywords:  has-unit-tests needs-dev-note        |     Focuses:
  needs-docs needs-user-docs 2nd-opinion needs-  |  performance
  testing changes-requested                      |
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Comment (by adamsilverstein):

 > stopping the needless generation of never used thumbnails just because
 the size definition was added

 The tricky part there is knowing which images are actually needed. Waiting
 until they are requested

 > Click on the “relative usage tab” to get a good visual
 https://caniuse.com/webp

 Neat, I hadn't seen this before.

 > mobile safari running on iOS 13 and earlier, that’s a tiny number that
 probably should be given some consideration if only because serving a
 larger fall back on mobile would be very bad practice.

 this would suggest keeping a much smaller size as JPEG, right?

 > Comparing SSIM is a bit more complicated than just looking at file size
 but there is data out there on this.

 yes, we wanted to repeat the studies in a WordPress context though, since
 our image generation stack is somewhat unique.

 > I do think you need to generate a full size image (not original) in jpeg
 format as a fallback. Just one though. I then think there ought to be a
 filter to enable generating Jpegs of all sizes, vs the default which
 should just be the full size

 Right, we have discussed this before, maybe adding a new full-original-
 mime "size".

 > I still feel needs a user facing checkbox on the media setting page for
 “Enable modern image format conversion [ ] WebP [ ] AVIF, etc.., With
 those off by default on upgrades for at least a few versions, and on by
 default on new installs.

 I don't agree we need a checkbox, to me this would be confusing for users.

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Ticket URL: <https://core.trac.wordpress.org/ticket/55443#comment:152>
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