It appears that when read only mode ($wgReadOnly) is active, you might also see this error.
When you see this error message on pages or for some files in your file list, you can try to remove $wgReadOnly from your LocalSettings.php.
Topic on Manual talk:Common errors and symptoms
Feel free to add that paragraph
Thank you for the quick reply.
I do not have permission to edit semi-protected pages. Perhaps someone who does have permission can add the following underneath the existing paragraph of 'Unable to save thumbnail to destination':
This error can also occur when read only mode ($wgReadOnly) has been set in LocalSettings.php. You can try to remove $wgReadOnly to see if that solves the issue for you.
I have checked section 2.2.6 Unable to save thumbnail to destination and your proposal has been integrated successfully, so I close the topic. Thanks for you collaboration. -- Christian 🇫🇷 FR (talk) 08:56, 7 November 2024 (UTC)