'filesize' metadata not updated after resizing media

[vertisoft]

It seems like WordPress does not update the 'filesize' metadata after an image is modified through the media library. The details panel in the media library displays the original file size instead of the 'new' file size.

Environment

• WordPress: 6.3.3-alpha-56924
• PHP: 8.2.10
• Server: Apache
• Database: mysqli (Server: 5.7.31 / Client: mysqlnd 8.2.10)
• Browser: Chrome 118.0.0.0 (Windows 10/11)
• MU-Plugins: None activated
• Plugins:
  • WordPress Beta Tester 3.5.4

The following optional modules are not currently installed on our server:

• exif
• fileinfo
• imagick

Steps to Reproduce

1. Upload a new image in the media library
2. Switch to the 'list' view in the media library to test the attachment page.
3. Note the file size (ie. 22 KB)
4. Resize the image by clicking on 'Edit Image', then 'Scale Image' (in my test case, I resized the image from 1920x1080 to 200x113)
5. Click 'Update'
6. The 'Dimensions' field is correctly updated, but 'File size' remains the same (22 KB)

Expected Results

The 'File size' should display the new file size (ie. 3.3 KB)

Actual Results

The 'File size' field displays the size of the original image, before it was resized.

Here is the value of the '_wp_attachment_metadata' field in the database after the media is resized:

a:6:{s:5:"width";i:200;s:6:"height";i:113;s:4:"file";s:31:"2023/10/Test-e1697729884174.png";s:8:"filesize";i:22990;s:5:"sizes";a:5:{s:6:"medium";a:5:{s:4:"file";s:16:"Test-300x169.png";s:5:"width";i:300;s:6:"height";i:169;s:9:"mime-type";s:9:"image/png";s:8:"filesize";i:4852;}s:5:"large";a:5:{s:4:"file";s:17:"Test-1024x576.png";s:5:"width";i:1024;s:6:"height";i:576;s:9:"mime-type";s:9:"image/png";s:8:"filesize";i:18748;}s:9:"thumbnail";a:5:{s:4:"file";s:16:"Test-150x150.png";s:5:"width";i:150;s:6:"height";i:150;s:9:"mime-type";s:9:"image/png";s:8:"filesize";i:3006;}s:12:"medium_large";a:5:{s:4:"file";s:16:"Test-768x432.png";s:5:"width";i:768;s:6:"height";i:432;s:9:"mime-type";s:9:"image/png";s:8:"filesize";i:13044;}s:9:"1536x1536";a:5:{s:4:"file";s:17:"Test-1536x864.png";s:5:"width";i:1536;s:6:"height";i:864;s:9:"mime-type";s:9:"image/png";s:8:"filesize";i:30857;}}s:10:"image_meta";a:12:{s:8:"aperture";s:1:"0";s:6:"credit";s:0:"";s:6:"camera";s:0:"";s:7:"caption";s:0:"";s:17:"created_timestamp";s:1:"0";s:9:"copyright";s:0:"";s:12:"focal_length";s:1:"0";s:3:"iso";s:1:"0";s:13:"shutter_speed";s:1:"0";s:5:"title";s:0:"";s:11:"orientation";s:1:"0";s:8:"keywords";a:0:{}}}

The "filesize" metadata has the value '22990' instead of '3033'.

[vertisoft]

Test image

[vertisoft]

Before resizing

[vertisoft]

After resizing

[antpb]

this was mentioned in the recent Media component meeting and we agreed to move it to 6.6. Should be a simple write to update the metadata on resize. Keeping it top of mind. :)

### What
This PR fixes the wrong file size displayed in the medial library when a user resizes an image. At the same time, if the user decides to revert the changes made to the image, this PR makes possible to revert to the original file size.

### Why
This PR solves the issue described in the following Trac ticket: https://core.trac.wordpress.org/ticket/59684

### How

• In the wp_save_image function I collect the array returned by wp_save_image_file and add it to the attachment metadata array as $meta['filesize']
  • This allows to show the correct file size when the image is scaled
• Before doing this I save the original filesize in in the $backup_sizes array
  • This allows to retrieve the original file size in case the user reverts the changes made to the image size
• In the wp_restore_image function I then read back from $backup_sizes the original file size and restore it when the user reverts back to the original size

[rajinsharwar]

Test Report

This report validates that the indicated patch addresses the issue.

Patch tested: ​https://github.com/WordPress/wordpress-develop/pull/6406

### Environment

• WordPress: 6.6-beta2-58392-src
• PHP: 8.3.0
• Server: NGINX
• Browser: Chrome

Actual Results

• ✅ The file size is now showing smaller when resized to a smaller resolution.

Before Patch

After Patch

[gauravsingh7]

Tested this patch. Seems to be working fine on my end.
The image size is getting updated after downscaling it.

[oglekler]

@antpb can you, please, take a look at this patch? We have RC1 later today )
Thank you!

[audrasjb]

As per today's bugscrub, we're moving this to 6.7 as it wasn't committed in time for RC1.

[joedolson]

Updating the description's reproduction steps to specify that this test needs to be performed in the attachment details page, not in the media modal. Unfortunately, the tests by @rajinsharwar are not valid, because they were performed in the media modal.