I don't see what this has to do with Special:UncategorizedTemplates. It's just a parser issue.

@S0ring: Do you plan to work on fixing this task, as you increased the priority of this task? The Priority field summarizes and reflects reality and does not cause it.

@Aklapper: I just wanted to get your attention to this issue which it blocks our migration on 3 wikis. But meanwhile the priority has been changed from High to Needs Triage.

@S0ring: "My attention" does not change or fix anything. :) Please don't fiddle with the Priority field to get attention. Thanks.

@S0ring, to confirm if I'm understanding you correctly, is the issue here that — there's a template with the following contents:

<div>
{| class="cmbox"  style="border: 2px; border-style: solid; border-color: #8E2043; width: 100%; vertical-align: middle;"
|-
| class="cmbox-image" style="vertical-align: middle; width: 70px"|[[Datei:mb-achtung.png|none|link=]]
| class="cmbox-text"|{{{1}}}
|}
</div>

On MediaWiki 1.39, that template displays the image (mb-achtung.png). However, after upgrading to MediaWiki 1.43, the image is no longer displayed.
Is that correct, or am I misunderstanding something? (/genuine question)

In T389464#10833511, @A_smart_kitten wrote:

@S0ring, to confirm if I'm understanding you correctly, is the issue here that — there's a template with the following contents:

<div>
{| class="cmbox"  style="border: 2px; border-style: solid; border-color: #8E2043; width: 100%; vertical-align: middle;"
|-
| class="cmbox-image" style="vertical-align: middle; width: 70px"|[[Datei:mb-achtung.png|none|link=]]
| class="cmbox-text"|{{{1}}}
|}
</div>

On MediaWiki 1.39, that template displays the image (mb-achtung.png). However, after upgrading to MediaWiki 1.43, the image is no longer displayed.
Is that correct, or am I misunderstanding something? (/genuine question)

Yes, this is the case. After migration 1.35 -> 1.39 with the same templates the images were displayed, but after 1.39 -> 1.43 no more.

Thanks for the confirmation! I'll see if I can try to reproduce the issue when I get a chance (hopefully in the next week or so). Feel free to ping me on this task for an update if it's been some time since this comment & I haven't said anything more.
(Of course, anyone else is welcome to attempt to reproduce this before me if they wish to do so :))

@S0ring to assist in reproducing the issue, if possible, please could you also confirm:

• the site/interface language of the wiki(s) in question
• the extensions & skins that are installed on the wiki(s) in question (in case any of them are causing the issue here)

If the wiki(s) in question have any custom configuration settings that have been set for them (e.g., in LocalSettings.php), it may also help with reproducing the issue if you're able to share the values of these custom configuration variables. However, please be careful to not share any private/confidential data (e.g. passwords) that might also be present in your wiki's configuration file :)

As a side note, please could you also confirm whether or not images are correctly displayed in non-template pages following the upgrade to MW 1.43?

Thanks to your comments regarding which extensions & skins that are installed on the wiki(s).

It gives me the idea to deactivate the Pivot skin which was installed on all 3 affected wikis and it occured this is actually the culprit: by using a different skin (i.e. vector) the images of the templates are displayed.

Replacing pivot-REL1_43 with pivot-master version [1] didn't help, the issue isn't fixed. Actually there aren't relevant changes so far [2]

[1] https://github.com/wikimedia/mediawiki-skins-Pivot
[2] https://github.com/wikimedia/mediawiki-skins-Pivot/compare/master...REL1_43

Thanks for the note, and no problem! Rerouting this issue to MediaWiki-skins-Pivot :)

I wouldn't be surprised if "not displayed" means that the image is responsively sized to be 0x0 pixels, because the text content in the template is wider than the page width.
Responsively sizing images is harder than people think.

I don't know any wikis that have Pivot installed, so difficult to quickly confirm if so.

<div>
{| class="cmbox"  style="border: 2px; border-style: solid; border-color: #8E2043; width: 100%; vertical-align: middle;"
|-
| class="cmbox-image" style="vertical-align: middle; width: 70px"|[[File:Fire (Element) Icon.png|none|link=]]
| class="cmbox-text"|{{{1}}}
|}
</div>

To confirm: I have Mediawiki 1.43.1 installed, and the latest Pivot.
Using the exact content provided, and just swapping to to an existing image, shows the problem is likely in the CSS somewhere.

Removing the |none parameter on the image fixes the issue. And yes, when no image size is set, and |none is set the image shows as 0px (putting a border on its element showed me it does display, it's just displaying at 0px).