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Fix: Skip scaled image sideload for images below big image threshold#75990

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adamsilverstein:fix/skip-scaled-sideload-below-threshold
Mar 1, 2026
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Fix: Skip scaled image sideload for images below big image threshold#75990
adamsilverstein merged 2 commits intoWordPress:trunkfrom
adamsilverstein:fix/skip-scaled-sideload-below-threshold

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@adamsilverstein adamsilverstein commented Feb 27, 2026 •
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Summary

Adds a dimension check before queuing the scaled image sideload, so that images below the big image size threshold (default 2560px) are not incorrectly processed as scaled images.

Problem

After #75817 ("Fix client-side media file naming"), the generateThumbnails() function unconditionally queues a "scaled" sideload for all images when bigImageSizeThreshold is set, regardless of actual image dimensions. This causes the PHP handler to set metadata['original_image'] even for small images that don't need scaling.

This breaks the big-image-size-threshold.spec.js E2E test at line 302, which correctly expects original_image to be undefined for undersized images.

Root cause chain:

  1. packages/upload-media/src/store/private-actions.ts — if ( bigImageSizeThreshold && attachment.id ) has no dimension check
  2. A sideload with image_size: 'scaled' is sent to the server even for small images
  3. The PHP handler sees image_size === 'scaled' and unconditionally sets metadata['original_image']

Fix

Uses createImageBitmap() to check the source file dimensions before queuing the scaled sideload. The sideload is only queued when width or height exceeds bigImageSizeThreshold, matching WordPress core's wp_create_image_subsizes() behavior.

Test coverage

Adds 8 unit tests for generateThumbnails in packages/upload-media/src/store/test/actions.ts, which previously had no test coverage. The tests verify:

  • Images below the threshold do not get a scaled sideload
  • Images above the threshold do get a scaled sideload with the correct attachment ID
  • Images where only the height exceeds the threshold are scaled (width OR height check)
  • No scaling when bigImageSizeThreshold is not set in settings
  • No scaling when the attachment has no ID
  • Sideload items are created for each missing image size
  • Early return when the item has no attachment
  • Images exactly at the threshold are not scaled (> not >=, matching WP core)

These tests were verified to fail against the pre-fix code, confirming they catch the bug.

Testing instructions

  • Run npm run test:unit -- --testPathPattern="packages/upload-media/src/store/test/actions" — all 21 tests pass
  • Run npm run test:e2e -- test/e2e/specs/editor/various/big-image-size-threshold.spec.js
  • Confirm all 3 E2E tests pass (above threshold scaled, below threshold not scaled, custom naming)
  • Upload a small image (below 2560px) and verify no original_image in attachment metadata
  • Upload a large image (above 2560px) and verify -scaled version is created correctly AND original_image in attachment metadata

Screenshots

Baseline server processing

server processing

Before fix, note extra file

extra

After fix

on pr

With large image

needs scaling

Scaled still working

scaled size

@adamsilverstein adamsilverstein added the Backport to WP 7.0 Beta/RC Pull request that needs to be backported to the WordPress major release that's currently in beta label Feb 27, 2026
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github-actions bot commented Feb 27, 2026

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Co-authored-by: adamsilverstein <[email protected]>

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@adamsilverstein adamsilverstein added [Type] Bug An existing feature does not function as intended [Feature] Client Side Media Media processing in the browser with WASM [Status] In Progress Tracking issues with work in progress labels Feb 27, 2026
@adamsilverstein adamsilverstein self-assigned this Mar 1, 2026
@github-project-automation github-project-automation bot moved this to 🔎 Needs Review in WordPress 7.0 Editor Tasks Mar 1, 2026
@adamsilverstein adamsilverstein moved this from 🔎 Needs Review to 🏗️ In Progress in WordPress 7.0 Editor Tasks Mar 1, 2026
@adamsilverstein @claude
Fix: Skip scaled image sideload for images below big image threshold
3f6898e 
Add a dimension check using createImageBitmap() before queuing the
scaled sideload. Only create the scaled version when the image width
or height exceeds bigImageSizeThreshold, matching WordPress core's
wp_create_image_subsizes() behavior. This prevents small images from
incorrectly getting original_image metadata set.

Co-Authored-By: Claude Opus 4.6 <[email protected]>
@adamsilverstein adamsilverstein force-pushed the fix/skip-scaled-sideload-below-threshold branch from c62e3f7 to 3f6898e Compare March 1, 2026 07:43
@adamsilverstein
Add tests for generateThumbnails scaled sideload
9ab3b68 
The generateThumbnails function had no test coverage,
so the bigImageSizeThreshold dimension check bug was
not caught. These tests verify scaled sideload behavior
for images above, below, and exactly at the threshold.
@adamsilverstein adamsilverstein moved this from 🏗️ In Progress to 🔎 Needs Review in WordPress 7.0 Editor Tasks Mar 1, 2026
@adamsilverstein adamsilverstein merged commit adacc44 into WordPress:trunk Mar 1, 2026
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@github-project-automation github-project-automation bot moved this from 🔎 Needs Review to ✅ Done in WordPress 7.0 Editor Tasks Mar 1, 2026
@github-actions github-actions bot added this to the Gutenberg 22.7 milestone Mar 1, 2026
@github-actions github-actions bot removed the Backport to WP 7.0 Beta/RC Pull request that needs to be backported to the WordPress major release that's currently in beta label Mar 1, 2026
gutenbergplugin pushed a commit that referenced this pull request Mar 1, 2026
@adamsilverstein @gutenbergplugin
Fix: Skip scaled image sideload for images below big image threshold (#…
9e6d6fa 
…75990)
@github-actions github-actions bot added the Backported to WP Core Pull request that has been successfully merged into WP Core label Mar 1, 2026
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github-actions bot commented Mar 1, 2026

I just cherry-picked this PR to the wp/7.0 branch to get it included in the next release: 9e6d6fa

gziolo pushed a commit that referenced this pull request Mar 3, 2026
@adamsilverstein @gziolo
Fix: Skip scaled image sideload for images below big image threshold (#…
d060a14 
…75990)
pull bot pushed a commit to tigefa4u/wordpress-develop that referenced this pull request Mar 5, 2026
@ellatrix
Gutenberg ref update.
e7d40e7 
CI run: WordPress#11167.

See #64595.

---

I've included a log of the Gutenberg changes with the following command:

git log --reverse --format="- %s" 022d8dd3d461f91b15c1f0410649d3ebb027207f..e499abfb843a43ac88455ca319220c5f181e1cf3 | sed 's|#\([0-9][0-9]*\)|https://github.com/WordPress/gutenberg/pull/\1|g; /github\.com\/WordPress\/gutenberg\/pull/!d' | pbcopy

- Add documentation for contentRole and listView block supports (WordPress/gutenberg#75903)
- Interactivity Router: fix back and forward navigation after refresh (WordPress/gutenberg#75927)
- Real-time collaboration: Fix disconnect dialog on navigate (WordPress/gutenberg#75886)
- Real Time Collab: Throttle syncing for inactive tabs. (WordPress/gutenberg#75843)
- Components: Specify line-height to avoid inheriting default values (WordPress/gutenberg#75880)
- Pattern Editing: Fix sibling blocks to edited pattern not being disabled (WordPress/gutenberg#75994)
- Sync connector PHP behavior with Core backport changes (WordPress/gutenberg#75968)
- Connectors: Avoid manual string concatenation (WordPress/gutenberg#75997)
- DataForm: fix field label for panel (should not be uppercase) (WordPress/gutenberg#75944)
- Views: add support for more overrides (all developer-defined config) (WordPress/gutenberg#75971)
- Use homeUrl instead of siteUrl for link badge evaluations (WordPress/gutenberg#75978)
- DataViews: Right-align `integer` and `number` fields (WordPress/gutenberg#75917)
- Navigation Link: Compare internal links by host instead of origin (WordPress/gutenberg#76015)
- Fix: Skip scaled image sideload for images below big image threshold (WordPress/gutenberg#75990)
- Client side media cherry pick for 7.0 (WordPress/gutenberg#75998)
- Show transform dropdown previews on focus as well as hover (WordPress/gutenberg#75940) (WordPress/gutenberg#75992)
- RTC: Fix syncing of emoji / surrogate pairs (WordPress/gutenberg#76049)
- [Real-time Collaboration] Fix sync issue on refresh (WordPress/gutenberg#76017)
- Real-time collaboration: Improve disconnect dialog (WordPress/gutenberg#75970)
- DataViews: Fix filter toggle flickering when there are locked or primary filters (WordPress/gutenberg#75913) (WordPress/gutenberg#76068)
- Connectors: Dynamically register providers from WP AI Client registry (WordPress/gutenberg#76014)
- PHP-only Blocks: Reflect bound attribute values in inspector controls (WordPress/gutenberg#76040)
- Fix: Set quality and strip metadata in client-side image resize (WordPress/gutenberg#76029)
- RTC: Prevent duplicate poll cycles (WordPress/gutenberg#76059)
- RTC: Fix stale CRDT document persisted on save (WordPress/gutenberg#75975)
- RTC: Disable multiple collaborators if meta boxes are present (WordPress/gutenberg#75939)
- Directly inject styles in overlay to make styles stay consistently mounted (WordPress/gutenberg#75700)
- Real-time collaboration: Fix comment syncing on site editor (WordPress/gutenberg#75746)
- Real-time Collaboration: Bug fix for CRDT user selection and add tests (WordPress/gutenberg#75075)
- RTC: Updates from backport PR (WordPress/gutenberg#75711)
- RTC: Fix undefined array_first() call in sync storage (WordPress/gutenberg#75869)
- RTC: Fix fallthrough for sync update switch statement (WordPress/gutenberg#76060)
- Real-time collaboration: Remove block client IDs from Awareness, fix "Show Template" view (WordPress/gutenberg#75590)
- RTC: Add session activity notifications (WordPress/gutenberg#76065)
- Prevent non-reproducible Sass/CSS builds. (WordPress/gutenberg#76098)
- Block toolbar and context menu: hide pattern actions in Revisions UI (WordPress/gutenberg#76066)
- Try enabling style variation transforms for blocks in contentOnly mode (WordPress/gutenberg#75761)
- Block toolbar: hide styles dropdown in Revisions UI (WordPress/gutenberg#76119)
- Image block: fix lightbox srcset size (WordPress/gutenberg#76092)
- Fix writing flow navigation for annotation style, or any other block with border radius (WordPress/gutenberg#76072)
- Image: Hide 'Set as featured image' for in-editor revisions (WordPress/gutenberg#76123)
- Connectors: Gate unavailable install actions behind install capability (WordPress/gutenberg#75980)
- build: Exclude experimental pages from Core builds (WordPress/gutenberg#76038)
- HTML & Shortcode: Disable viewport visibility support (WordPress/gutenberg#76138)
- RTC: Verify client ID to avoid awareness mutation (WordPress/gutenberg#76056)
- wp-build: Do not remove Core's default script modules registration (WordPress/gutenberg#75705)
- wp-build: Deregister script modules before re-registering (WordPress/gutenberg#75909)
- Remove `! function_exists()` checks from PHP templates (WordPress/gutenberg#76062)
- Connectors: Update page identifier to options-connectors (WordPress/gutenberg#76156)
- Connectors: Align init hook priorities with Core overrides (WordPress/gutenberg#76161)
- Icon Block: Clean up selectors config (WordPress/gutenberg#75786)
- Icons: Fix incorrect icon slug (WordPress/gutenberg#76165)
- RTC: Enable RTC by default (WordPress/gutenberg#75739)
- Rename and visibility modals: gate shortcuts behind canEditBlock to prevent triggering in revisions UI (WordPress/gutenberg#76168)
- Fix: Block style variations not rendering in Site Editor Patterns page (WordPress/gutenberg#76122)
- Client-side media processing: only use media upload provider when not in preview mode (WordPress/gutenberg#76124)
- Notes: Disable for in-editor revisions (WordPress/gutenberg#76180)
- Core Data: Support reading revision data in useEntityProp (fixes footnotes in revisions UI) (WordPress/gutenberg#76106)
- Client-side media processing: Try plumbing invalidation to the block-editor's mediaUpload onSuccess callback (WordPress/gutenberg#76173)
- Connectors: Improve responsive layout on small screens (WordPress/gutenberg#76186)
- Interactivity API: Fix router initialization race condition on Safari/Firefox (WordPress/gutenberg#76053) (WordPress/gutenberg#76191)
- Interactivity: Fix crypto.randomUUID crash in non-secure contexts (WordPress/gutenberg#76151)


git-svn-id: https://develop.svn.wordpress.org/trunk@61843 602fd350-edb4-49c9-b593-d223f7449a82
markjaquith pushed a commit to markjaquith/WordPress that referenced this pull request Mar 5, 2026
@ellatrix
Gutenberg ref update.
f51b21a 
CI run: WordPress/wordpress-develop#11167.

See #64595.

---

I've included a log of the Gutenberg changes with the following command:

git log --reverse --format="- %s" 022d8dd3d461f91b15c1f0410649d3ebb027207f..e499abfb843a43ac88455ca319220c5f181e1cf3 | sed 's|#\([0-9][0-9]*\)|https://github.com/WordPress/gutenberg/pull/\1|g; /github\.com\/WordPress\/gutenberg\/pull/!d' | pbcopy

- Add documentation for contentRole and listView block supports (WordPress/gutenberg#75903)
- Interactivity Router: fix back and forward navigation after refresh (WordPress/gutenberg#75927)
- Real-time collaboration: Fix disconnect dialog on navigate (WordPress/gutenberg#75886)
- Real Time Collab: Throttle syncing for inactive tabs. (WordPress/gutenberg#75843)
- Components: Specify line-height to avoid inheriting default values (WordPress/gutenberg#75880)
- Pattern Editing: Fix sibling blocks to edited pattern not being disabled (WordPress/gutenberg#75994)
- Sync connector PHP behavior with Core backport changes (WordPress/gutenberg#75968)
- Connectors: Avoid manual string concatenation (WordPress/gutenberg#75997)
- DataForm: fix field label for panel (should not be uppercase) (WordPress/gutenberg#75944)
- Views: add support for more overrides (all developer-defined config) (WordPress/gutenberg#75971)
- Use homeUrl instead of siteUrl for link badge evaluations (WordPress/gutenberg#75978)
- DataViews: Right-align `integer` and `number` fields (WordPress/gutenberg#75917)
- Navigation Link: Compare internal links by host instead of origin (WordPress/gutenberg#76015)
- Fix: Skip scaled image sideload for images below big image threshold (WordPress/gutenberg#75990)
- Client side media cherry pick for 7.0 (WordPress/gutenberg#75998)
- Show transform dropdown previews on focus as well as hover (WordPress/gutenberg#75940) (WordPress/gutenberg#75992)
- RTC: Fix syncing of emoji / surrogate pairs (WordPress/gutenberg#76049)
- [Real-time Collaboration] Fix sync issue on refresh (WordPress/gutenberg#76017)
- Real-time collaboration: Improve disconnect dialog (WordPress/gutenberg#75970)
- DataViews: Fix filter toggle flickering when there are locked or primary filters (WordPress/gutenberg#75913) (WordPress/gutenberg#76068)
- Connectors: Dynamically register providers from WP AI Client registry (WordPress/gutenberg#76014)
- PHP-only Blocks: Reflect bound attribute values in inspector controls (WordPress/gutenberg#76040)
- Fix: Set quality and strip metadata in client-side image resize (WordPress/gutenberg#76029)
- RTC: Prevent duplicate poll cycles (WordPress/gutenberg#76059)
- RTC: Fix stale CRDT document persisted on save (WordPress/gutenberg#75975)
- RTC: Disable multiple collaborators if meta boxes are present (WordPress/gutenberg#75939)
- Directly inject styles in overlay to make styles stay consistently mounted (WordPress/gutenberg#75700)
- Real-time collaboration: Fix comment syncing on site editor (WordPress/gutenberg#75746)
- Real-time Collaboration: Bug fix for CRDT user selection and add tests (WordPress/gutenberg#75075)
- RTC: Updates from backport PR (WordPress/gutenberg#75711)
- RTC: Fix undefined array_first() call in sync storage (WordPress/gutenberg#75869)
- RTC: Fix fallthrough for sync update switch statement (WordPress/gutenberg#76060)
- Real-time collaboration: Remove block client IDs from Awareness, fix "Show Template" view (WordPress/gutenberg#75590)
- RTC: Add session activity notifications (WordPress/gutenberg#76065)
- Prevent non-reproducible Sass/CSS builds. (WordPress/gutenberg#76098)
- Block toolbar and context menu: hide pattern actions in Revisions UI (WordPress/gutenberg#76066)
- Try enabling style variation transforms for blocks in contentOnly mode (WordPress/gutenberg#75761)
- Block toolbar: hide styles dropdown in Revisions UI (WordPress/gutenberg#76119)
- Image block: fix lightbox srcset size (WordPress/gutenberg#76092)
- Fix writing flow navigation for annotation style, or any other block with border radius (WordPress/gutenberg#76072)
- Image: Hide 'Set as featured image' for in-editor revisions (WordPress/gutenberg#76123)
- Connectors: Gate unavailable install actions behind install capability (WordPress/gutenberg#75980)
- build: Exclude experimental pages from Core builds (WordPress/gutenberg#76038)
- HTML & Shortcode: Disable viewport visibility support (WordPress/gutenberg#76138)
- RTC: Verify client ID to avoid awareness mutation (WordPress/gutenberg#76056)
- wp-build: Do not remove Core's default script modules registration (WordPress/gutenberg#75705)
- wp-build: Deregister script modules before re-registering (WordPress/gutenberg#75909)
- Remove `! function_exists()` checks from PHP templates (WordPress/gutenberg#76062)
- Connectors: Update page identifier to options-connectors (WordPress/gutenberg#76156)
- Connectors: Align init hook priorities with Core overrides (WordPress/gutenberg#76161)
- Icon Block: Clean up selectors config (WordPress/gutenberg#75786)
- Icons: Fix incorrect icon slug (WordPress/gutenberg#76165)
- RTC: Enable RTC by default (WordPress/gutenberg#75739)
- Rename and visibility modals: gate shortcuts behind canEditBlock to prevent triggering in revisions UI (WordPress/gutenberg#76168)
- Fix: Block style variations not rendering in Site Editor Patterns page (WordPress/gutenberg#76122)
- Client-side media processing: only use media upload provider when not in preview mode (WordPress/gutenberg#76124)
- Notes: Disable for in-editor revisions (WordPress/gutenberg#76180)
- Core Data: Support reading revision data in useEntityProp (fixes footnotes in revisions UI) (WordPress/gutenberg#76106)
- Client-side media processing: Try plumbing invalidation to the block-editor's mediaUpload onSuccess callback (WordPress/gutenberg#76173)
- Connectors: Improve responsive layout on small screens (WordPress/gutenberg#76186)
- Interactivity API: Fix router initialization race condition on Safari/Firefox (WordPress/gutenberg#76053) (WordPress/gutenberg#76191)
- Interactivity: Fix crypto.randomUUID crash in non-secure contexts (WordPress/gutenberg#76151)

Built from https://develop.svn.wordpress.org/trunk@61843


git-svn-id: http://core.svn.wordpress.org/trunk@61130 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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@swissspidy swissspidy swissspidy approved these changes

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Labels

Backported to WP Core Pull request that has been successfully merged into WP Core [Feature] Client Side Media Media processing in the browser with WASM [Status] In Progress Tracking issues with work in progress [Type] Bug An existing feature does not function as intended

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WordPress 7.0 Editor Tasks
Status: ✅ Done

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Gutenberg 22.7

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@adamsilverstein @swissspidy