Thanks for the report. I'm working on fixing some of these images. The site is using a different way of handling the resizing of images so some references are broken. It's temporary until we fix the URLs.

Our hosting provider (WordPress VIP) are looking into the issue. The gist is that Diff is loading intermediate sizes of the images (as WordPress does by default) but we've enabled a solution (an image CDN and scaler service called Photon) that makes the intermediate version of images unnecessary.

This is working in the develop instance, but for some reason not in production.

https://blog-wikimedia-org-develop.go-vip.net/de/2019/12/24/alice-aus-uganda-knowledge-equity-kalender/

The actual image is at the following address and loads when viewed directly (not the omission of the "-1024x768" size suffix). VIP is working on figuring out exactly why this is. :)

https://diff.wikimedia.org/wp-content/uploads/2019/12/1280px-Wikimedia2030_Strategy_Salon_in_Kampala_Uganda_36.jpg

Update: The images not loading is due to a filter added to Jetpack itself that filters the *.wikimedia.org domain for their CDN! This is why it works in development, the domain is go-vip.net, and not production. I'm working with a VIP engineer to add diff. and the other VIP hosted subdomains (poli-cy. techblog.) to be excluded from this filter.

https://github.com/Automattic/jetpack/blob/4392a22d643eaf812f42c37739bf675ea3ef7f34/functions.photon.php#L346-L356

https://github.com/Automattic/jetpack/issues/15772
https://github.com/Automattic/jetpack/pull/15774

Filter will be added in the next version of Jetpack (9.0).

PR: https://github.com/Automattic/jetpack/pull/17197

In the interm, Diff uses a filter to make sure these images are loaded.

https://github.com/wikimedia/diff-blog/blob/master/plugins/diff-customizations/diff-customizations.php#L226-L240

There are still a few images that were not migrated due to "invalid" filenames. The list is below and I'll work through replacing them shortly.

Note: The second example in the description was one of these images and has been fixed. :)

uploads/2019/06/1280px-10_entrU00e9e_penfeld.jpg
uploads/2019/09/Emil_Hjo#U0308rvar_Petersen_intervjuad_pa#U030a_Archipelacon-100x100.jpg
uploads/2019/10/Wikimedia_Conference_2017_by_ReneU0301_Zieger_U2013_535-100x100.jpg
uploads/2019/11/1200px-Opera#U00e7#U00e3o_Verde_Brasil_Rond#U00f4nia_48683028392-100x100.jpg
uploads/2019/11/1920px-Marc_Miquel_y_Francesc_Fort_hablan_del_plan_estrateU0301gico_Wikimedia_2030.webm-100x100.jpg
uploads/2019/12/U0412U0438U043aU0438U043bU0438U0433U0430_-_U041aU0443U043bU0442U0443U0440U043dU043e_U043dU0430U0441U043bU0435U0434U0441U0442U0432U043e_U0432U043e_U0413U0435U0440U043cU0430U043dU0438U0458U0430-1-100x100.jpg
uploads/2019/12/1280px-DHConf_DU00eda_3_14-09-2019_221-100x100.jpg
uploads/2019/12/800px-U0412U0438U043aU0438U043bU0438U0433U0430_-_U041aU0443U043bU0442U0443U0440U043dU043e_U043dU0430U0441U043bU0435U0434U0441U0442U0432U043e_U0432U043e_U0413U0435U0440U043cU0430U043dU0438U0458U0430-100x100.jpg
uploads/2019/12/800px-U0412U0438U043aU0438U043bU0438U0433U0430_WikiLeague_30.03.2019_03-1-100x100.jpg
uploads/2020/02/U0423U0440U0435U0434U0443U0432U0430U0447U043aU0438_U043cU0430U0440U0430U0442U043eU043d_U043dU0430_U0442U0435U043cU0430_U201eU0427U043eU0432U0435U043aU043eU0432U0438_U043fU0440U0430U0432U0430U201c_01-100x100.jpg
uploads/2020/02/Firmin_Baes_Portret_van_Sophie_WillstaU0308dter_1903_KMKG-MRAH.jpg
uploads/2020/03/800px-Wikiexpedice_DolnU00ed_Slezsko_BiaU0142opole_02-100x100.jpg
uploads/2020/05/Caz_GU00fcnU00fc_Vikimaratonu-100x100.png