og:image URL refers to full-size thumbnail version of original instead the original
Closed, ResolvedPublicBUG REPORT
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	AntiCompositeNumber
	Jan 26 2026, 9:54 PM

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	F71611411: image.png
	Jan 26 2026, 9:54 PM

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Description

Steps to replicate the issue (include links if applicable):

Send a link to a file, or an article with a PageImage, on Discord
- for example, https://commons.wikimedia.org/wiki/File:Accordion2.png

What happens?:

Discord makes a request to https://images-ext-1.discordapp.net/external/_BYI8LzaVlCsouEstKryot7azEN6V-7oQBhV2vnJNK4/https/upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Accordion2.png/912px-Accordion2.png?format=webp&quality=lossless&width=213&height=300

What should have happened instead?:
The thumbnail should display.

Software version (on Special:Version page; skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

Details

Related Changes in Gerrit:

Subject	Author	Repo	Branch	Lines +/-
Move handling of ThumbnailSteps to media handlers	Func	mediawiki/core	REL1_43	+146 -114
Move handling of ThumbnailSteps to media handlers	Neriah	mediawiki/core	REL1_45	+146 -112
Move handling of ThumbnailSteps to media handlers	Neriah	mediawiki/core	REL1_44	+146 -112
Move handling of ThumbnailSteps to media handlers	Func	mediawiki/core	master	+146 -112
ThumbnailImage: Store physical size for the PageImages extension	Func	mediawiki/core	master	+16 -0
Use the physical size of the image for Open Graph tags	Func	mediawiki/extensions/PageImages	master	+4 -2

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Related Objects
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Status	Subtype	Assigned	Task
Resolved		MatthewVernon	T414805 FY 25/26 WE 5.4.10 Standard Thumbnail Sizes Only
Resolved		Ladsgroup	T402792 Consider rate limiting non-standard thumbnail sizes
Resolved	BUG REPORT	Func	T415598 og:image URL refers to full-size thumbnail version of original instead the original

Event Timeline

AntiCompositeNumber created this task.Jan 26 2026, 9:54 PM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptJan 26 2026, 9:54 PM

taavi edited projects, added: SRE, Traffic; removed: WMF-General-or-Unknown.Jan 26 2026, 9:55 PM

This started happening within the last month or so. It doesn't happen for every request for every thumbnail, but seems to be more likely after the first request. Discord uses Google Cloud IPs most of the time.

Johannnes89 subscribed.Jan 26 2026, 10:30 PM

<meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Accordion2.png/912px-Accordion2.png">

The ogp.me tag is listing the thumbnail variant of the fullsize, instead of the fullsize

TheDJ renamed this task from High rate of broken thumbnails on Discord embeds of links to Wikimedia sites to OGP lists thumbnail version of fullsize instead the fullsize version itself.Jan 26 2026, 11:03 PM

TheDJ added a parent task: T414805: FY 25/26 WE 5.4.10 Standard Thumbnail Sizes Only.

TheDJ renamed this task from OGP lists thumbnail version of fullsize instead the fullsize version itself to OGP lists fullsize thumbnail version of original instead the original itself.Jan 26 2026, 11:11 PM

In T415598#11555931, @TheDJ wrote:

The ogp.me tag is listing the thumbnail variant of the fullsize, instead of the fullsize

I'm not sure I would consider this a bug. Not all of our images are web-safe (TIFFs for example), so the fullsize thumbnail is necessary for compatibility.

In T415598#11555961, @AntiCompositeNumber wrote:

In T415598#11555931, @TheDJ wrote:

The ogp.me tag is listing the thumbnail variant of the fullsize, instead of the fullsize

I'm not sure I would consider this a bug. Not all of our images are web-safe (TIFFs for example), so the fullsize thumbnail is necessary for compatibility.

The media handler class should take care of that. Png is certainly websafe. So it would be a bug in this particular case.

It does a straight $file->transform(), which indeed has this effect of creating a thumbnail according to the specified instructions. There are other entrypoints that should apply the correct logic before deciding to do a transform. Not sure which is the most appropriate one of the top of my head.

TheDJ added a parent task: T402792: Consider rate limiting non-standard thumbnail sizes.Jan 28 2026, 4:01 PM

Func subscribed.Jan 31 2026, 10:36 PM

Change #1235542 had a related patch set uploaded (by Func; author: Func):

[mediawiki/core@master] [WIP] Move handling of ThumbnailSteps to TransformationalImageHandler

https://gerrit.wikimedia.org/r/1235542

gerritbot added a project: Patch-For-Review.Feb 1 2026, 1:23 AM

Func added a project: MediaWiki-File-management.Feb 1 2026, 1:27 AM

Maintenance_bot added a project: Commons.Feb 1 2026, 1:32 AM

Func removed projects: Traffic, SRE.Feb 1 2026, 4:09 AM

It's very unfortunate that the original patch for T360589 got merged, the test cases are so broken and assert the wrong behaviour. ~~And the unchanged size was used for the actual scaling, so now we have thumbs smaller than the claimed size in the production storage~~.

Edit: thumbs via 404 transform are not affected.

Peachey88 removed a project: Commons.Feb 1 2026, 4:27 AM

Change #1235544 had a related patch set uploaded (by Func; author: Func):

[mediawiki/core@master] ThumbnailImage: Store physical width for the PageImages extension

https://gerrit.wikimedia.org/r/1235544

Change #1235545 had a related patch set uploaded (by Func; author: Func):

[mediawiki/extensions/PageImages@master] Use the physical size of the image for Open Graph tags

https://gerrit.wikimedia.org/r/1235545

Mr._Starfleet_Command subscribed.Feb 1 2026, 11:12 PM

Change #1235542 merged by jenkins-bot:

[mediawiki/core@master] Move handling of ThumbnailSteps to media handlers

https://gerrit.wikimedia.org/r/1235542

ReleaseTaggerBot added a project: MW-1.46-notes (1.46.0-wmf.16; 2026-02-17).Feb 12 2026, 6:00 PM

Krinkle renamed this task from OGP lists fullsize thumbnail version of original instead the original itself to og:image URL refers to full-size thumbnail version of original instead the original.Feb 12 2026, 6:36 PM

Vermont subscribed.Feb 24 2026, 4:03 AM

revi subscribed.Feb 28 2026, 3:46 PM

It should be fixed now linking to the originals instead. Can someone confirm this?

Mr._Starfleet_Command unsubscribed.Mar 4 2026, 2:01 AM

confirmed fixed

TheDJ reassigned this task from TheDJ to Func.Mar 4 2026, 2:30 PM

AntiCompositeNumber mentioned this in T419325: Discord thumbnail embeds for Wikimedia links still mostly broken.Mar 7 2026, 9:30 PM

Change #1249927 had a related patch set uploaded (by Neriah; author: Func):

[mediawiki/core@REL1_45] Move handling of ThumbnailSteps to media handlers

https://gerrit.wikimedia.org/r/1249927

03:28 < Neriah63> [12:25:40] <Neriah63> Hi
03:28 < Neriah63> [12:25:42] <Neriah63> https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1235542
03:28 < Neriah63> [12:25:49] <Neriah63> I would think this also requires a change in 1.43/1.44/1.45. Am I mistaken?
03:28 < Neriah63> [12:25:59] <Neriah63> It forced us to add handling in common.js for images that are not handled at 
                  the server level, and because of that it takes 2 seconds for those images to load...
[..]
03:33 < bawolff> Is this causing problems for people using instant commons? Because otherwise it doesn't seem that 
                 critical to backport as most people aren't using $wgThumbnailSteps for local uploads
03:35 < Neriah63> Yes, we have the problem for instant commons.

So maybe this needs backporting.

Change #1249953 had a related patch set uploaded (by Neriah; author: Func):

[mediawiki/core@REL1_44] Move handling of ThumbnailSteps to media handlers

https://gerrit.wikimedia.org/r/1249953

Change #1251297 had a related patch set uploaded (by Func; author: Func):

[mediawiki/core@REL1_43] Move handling of ThumbnailSteps to media handlers

https://gerrit.wikimedia.org/r/1251297

Change #1249953 merged by jenkins-bot:

[mediawiki/core@REL1_44] Move handling of ThumbnailSteps to media handlers

https://gerrit.wikimedia.org/r/1249953

Change #1249927 merged by jenkins-bot:

[mediawiki/core@REL1_45] Move handling of ThumbnailSteps to media handlers