The kind Ilario Valdelli WMCH (User:Ilario) confirmed that all the staff photos that are on the Wikimedia CH website are in Creative Commons BY-SA 4.0:

https://wikimedia.ch/about/staff-members/

Here the archived version:

https://web.archive.org/web/20221206040842/https://wikimedia.ch/en/about/staff-members/

Here the license page:

https://wikimedia.ch/en/creative-commons/

So we can import these 12 high-definition photos from the WMCH WordPress website into Wikimedia Commons:

• https://wikimedia.ch/wp-content/uploads/2019/08/wikimedia-jenny-ebermann.jpg - Jenny Ebermann
  • https://commons.wikimedia.org/wiki/File:Jenny_Ebermann_-_2019_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2022/08/maurus-achermann-wmch-1600.jpg - Maurus Achermann
  • https://commons.wikimedia.org/wiki/File:Maurus_Achermann_-_2022_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2022/08/lantus-alternativ-wmch.jpg - Ulrich Lantermann
  • https://commons.wikimedia.org/wiki/File:Ulrich_Lantermann_-_2022_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2019/09/wikimedia-flor-mechain.jpg - Flor Méchain
  • https://commons.wikimedia.org/wiki/File:Flor_M%C3%A9chain_-_2019_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2022/12/lia-beretta-880.jpg - Lia Beretta
  • https://commons.wikimedia.org/wiki/File:Lia_Beretta_-_2022_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2022/08/sandra-becker-wmch-1600.jpg - Sandra Becker
  • https://commons.wikimedia.org/wiki/File:Sandra_Becker_-_2022_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2022/09/amandine-wmch-850-website.jpg - Amandine Cabrio
  • https://commons.wikimedia.org/wiki/File:Amandine_Cabrio_-_2022_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2020/10/1600.jpg - Ilario Valdelli
  • https://commons.wikimedia.org/wiki/File:Ilario_Valdelli_-_2020_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2019/11/kerstin-sonnekalb-5-1.jpg - Kerstin Sonnekalb
  • https://commons.wikimedia.org/wiki/File:Kerstin_Sonnekalb_-_2019_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2019/09/wikimedia-ml-cognard.jpg - Marie-Louise Cognard
  • https://commons.wikimedia.org/wiki/File:Marie-Louise_Cognard_-_2019_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2021/07/stephane-maffli-staff-website-500-pix.jpg - Stéphane Maffli
  • https://commons.wikimedia.org/wiki/File:St%C3%A9phane_Maffli_-_2021_-_WMCH.jpg
• https://wikimedia.ch/wp-content/uploads/2021/03/marta-vidal-website-1600.jpg - Marta Vidal
  • https://commons.wikimedia.org/wiki/File:Marta_Vidal_-_2021_-_WMCH.jpg

Additional:

• Verify that the photos on Wikimedia Commons have the template "Personality rights" - https://commons.wikimedia.org/wiki/Template:Personality_rights