Look at Parsoid's output below for a localized thumbnail on cswiki.
```
$ echo "[[Soubor:Global_Temperature_Anomaly.svg|lang=cs|320px|okraj]]" | php bin/parse.php --domain cs.wikipedia.org
<p data-parsoid='{"dsr":[0,61,0,0]}'><span class="mw-image-border" typeof="mw:Image" data-parsoid='{"optList":[{"ck":"lang","ak":"lang=cs"},{"ck":"width","ak":"320px"},{"ck":"border","ak":"okraj"}],"dsr":[0,61,null,null]}'><a href="./Soubor:Global_Temperature_Anomaly.svg" data-parsoid="{}"><img resource="./Soubor:Global_Temperature_Anomaly.svg" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Global_Temperature_Anomaly.svg/320px-Global_Temperature_Anomaly.svg.png" decoding="async" lang="cs" data-file-width="1440" data-file-height="1000" data-file-type="drawing" height="222" width="320" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Global_Temperature_Anomaly.svg/480px-Global_Temperature_Anomaly.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Global_Temperature_Anomaly.svg/640px-Global_Temperature_Anomaly.svg.png 2x" data-parsoid='{"a":{"resource":"./Soubor:Global_Temperature_Anomaly.svg","lang":"cs","height":"222","width":"320"},"sa":{"resource":"Soubor:Global_Temperature_Anomaly.svg","lang":"lang=cs"}}'/></a></span></p>
```
The image resource doesn't have a language specific thumbnail (it has the lang="cs" attribute) whereas the legacy parser uses `https://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Global_Temperature_Anomaly.svg/langcs-320px-Global_Temperature_Anomaly.svg.png`.
Thanks to @vadim-kovalenko for the investigation.
---
===Original Bug Report===
Steps to Reproduce:
# Go to "Skleníkový efekt" ([[ https://cs.wikipedia.org/w/index.php?title=Sklen%C3%ADkov%C3%BD_efekt&oldid=19068554 | permalink ]]) on cswiki.
# Trigger preview of "globální oteplování" at the end of the third paragraph (links to [[ https://cs.wikipedia.org/wiki/Glob%C3%A1ln%C3%AD_oteplov%C3%A1n%C3%AD | Globální oteplování ]] on cswiki).
Actual Results:
- The preview image (a multilingual SVG file) is displayed with English captions.
Expected Results:
- The preview image is displayed with Czech (local) captions, just like it's displayed in the linked article.
| preview | article
| {F33935256} | {F33935258}
This could be related to T208620 but I'm reporting it separate for #page-previews.
If resolving the other task would also resolve this one, there is no other way to fix this and no need to track them separately, they can be merged.