*.jpg is not generated for scaled full size image.

[mitogh]

Steps to replicate

• Enable the WebP module
• Upload an image bigger than the 2560 or big_image_size_threshold (Use attached image)
  • https://github.com/WordPress/wordpress-develop/blob/trunk/src/wp-admin/includes/image.php#L275
• Upload the image.
• Observe the full-size image was created with a *webp extension for the full size image.

Image meta data stored in WordPress

Metadata of the image.

=> array(6) {
  ["width"]=>
  int(1707)
  ["height"]=>
  int(2560)
  ["file"]=>
  string(55) "2022/01/philip-myrtorp-hDBdvjk1b0s-unsplash-scaled.webp"
  ["sizes"]=>
  array(7) {
    ["medium"]=>
    array(4) {
      ["file"]=>
      string(48) "philip-myrtorp-hDBdvjk1b0s-unsplash-200x300.webp"
      ["width"]=>
      int(200)
      ["height"]=>
      int(300)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["large"]=>
    array(4) {
      ["file"]=>
      string(49) "philip-myrtorp-hDBdvjk1b0s-unsplash-683x1024.webp"
      ["width"]=>
      int(683)
      ["height"]=>
      int(1024)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["thumbnail"]=>
    array(4) {
      ["file"]=>
      string(48) "philip-myrtorp-hDBdvjk1b0s-unsplash-150x150.webp"
      ["width"]=>
      int(150)
      ["height"]=>
      int(150)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["medium_large"]=>
    array(4) {
      ["file"]=>
      string(49) "philip-myrtorp-hDBdvjk1b0s-unsplash-768x1152.webp"
      ["width"]=>
      int(768)
      ["height"]=>
      int(1152)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["1536x1536"]=>
    array(4) {
      ["file"]=>
      string(50) "philip-myrtorp-hDBdvjk1b0s-unsplash-1024x1536.webp"
      ["width"]=>
      int(1024)
      ["height"]=>
      int(1536)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["2048x2048"]=>
    array(4) {
      ["file"]=>
      string(50) "philip-myrtorp-hDBdvjk1b0s-unsplash-1365x2048.webp"
      ["width"]=>
      int(1365)
      ["height"]=>
      int(2048)
      ["mime-type"]=>
      string(10) "image/webp"
    }
    ["post-thumbnail"]=>
    array(4) {
      ["file"]=>
      string(50) "philip-myrtorp-hDBdvjk1b0s-unsplash-1568x2352.webp"
      ["width"]=>
      int(1568)
      ["height"]=>
      int(2352)
      ["mime-type"]=>
      string(10) "image/webp"
    }
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    string(1) "0"
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    string(1) "0"
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    string(1) "0"
    ["iso"]=>
    string(1) "0"
    ["shutter_speed"]=>
    string(1) "0"
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    string(1) "0"
    ["keywords"]=>
    array(0) {
    }
  }
  ["original_image"]=>
  string(39) "philip-myrtorp-hDBdvjk1b0s-unsplash.jpg"
}

This happens due to the new "full size" being scaled down to match the threshold from WordPress and prevents having a fallback *.jpg for the scaled size (full size).

Image used for testing this behavior.

[getsource]

Thanks so much for the report!

The original full size uploaded image (in JPEG) should still be there (as is listed in the meta under "original image").
Just to confirm, is that the case? This image could act as a fallback if images need to be re-generated at some point.

My understanding is that the intent is for WebP to be the primary format when that module is enabled, so this sounds to me like the intended behavior.

It sounds like the behavior is inconsistent, though, between uploading an image larger/smaller than the big_image_size_threshold. Since if it's smaller, the types would be mixed (although as you note, it has the benefit of acting as a larger sized fallback).

@adamsilverstein What do you think?

[mitogh]

The original full size uploaded image (in JPEG) should still be there (as is listed in the meta under "original image").
Just to confirm, is that the case? This image could act as a fallback if images need to be re-generated at some point.

That's correct, full-size image is still uploaded as specified on the meta but is the full-size image tho not the scaled version with the maximum dimensions set by WordPress.

Additionally, I think using the original image as a fallback does not provide a performance benefit, on the contrary, it loads a nonoptimized image in terms of size and quality to a device where modern images are not supported and instead a more appropriate size should be loaded as a fallback instead.

[adamsilverstein]

Fixed in #143

[mitogh]

Related with the following core ticket:

• https://core.trac.wordpress.org/ticket/53665