"Error creating thumbnail" message on SL wiki, breaking images
Erik Mondrian
On Dec 1, 2025, I noticed that images seem to be broken all across the official SL wiki, replaced by the following message: "Error creating thumbnail: Unable to save thumbnail to destination"
Nearly two weeks later and the issue still persists, affecting almost every wiki page I've looked at. Some examples include https://wiki.secondlife.com/wiki/Good_Building_Practices and https://wiki.secondlife.com/wiki/Third_Party_Viewer_Directory (where a couple images occasionally appear to show up okay, but not all of them).
This issue is especially problematic for pages like https://wiki.secondlife.com/wiki/Linden_Lab_Official:New_Linden_Homes_2019 which uses images to show off the various Premium LH themes of Bellisseria. Right now, it's just text, with all of the images missing.
Log In
Gloss Doll
I've definitely encountered this issue on the wiki as well.
I've seen this issue appear before on another organization's MediaWiki install, but I don't know exactly what the cause of the problem is.
In that organization I was able to do some exploratory googling on the organization's behalf to try and move us towards a solution.. and the results I found suggested that there might be either a permissions issue in relation to the creation of thumbnail images, something that broke when a version update was applied, some other misconfiguration (in the mistaken name of 'security') that resulted in a lack of ability for the image handling system to function, or possibly a media storage location that was full.
Resources I found:
"[RESOLVED] MW 1.21 Error creating thumbnail: Unable to save thumbnail to destination" mediawiki help thread
"Error creating thumbnail: Unable to save thumbnail to destination" (fixed) mediawiki help thread
"Error creating thumbnail: Unable to save thumbnail to destination" mediawiki help thread
...
Gloss Doll
...And perhaps most relevant, this article from the
MediaWiki help documentation
:MediaWiki Errors
Image Thumbnails not working and/or appearing
This section lists problems and solutions relating to thumbnails not rendering or displaying.
...
Unable to save thumbnail to destination
If you get the error "Error generating thumbnail / Error creating thumbnail: Unable to save thumbnail to destination" and the
$wgUploadDirectory
directory has the correct permissions (at all levels), check that $wgTmpDirectory
actually exists. (Unlike some path variables such as $wgCacheDirectory
, $wgTmpDirectory
is not created at runtime.) A more detailed error message may be available if you turn on logging with $wgDebugLogFile
.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.