[MediaWiki-l] Image thumbnailing in MediaWiki

Krabina Bernhard krabina at kdz.or.at
Mon Jul 31 09:25:49 UTC 2017

Dear all,

thank you for your help, it is much appreciated.

An additional question regarding thumbnailing: do thumbs ever get deleted by MediaWiki?
They probably get deleted once the image gets deleted. But other than that, do all generated thumbnails exist as long as the image exists?


----- Am 29. Jul 2017 um 2:22 schrieb Brian Wolff bawolff at gmail.com:

> Hi,
> MediaWiki will by default only create image thumbs for needed sizes at
> time the size is used on a page. So for example when you add an image
> to a page, MW will create the thumbnail sizes needed to display an
> article. However, if the image is uploaded but never added to a normal
> page, then thumbnails for the image won't be generated (except for
> those needed on image description page, which are different sizes)
> There is a second mode mediawiki can operate in, where images are
> rendered on demand when someone views the image (so-called "404 thumb
> handling"). Wikimedia wikis use this mode. In this mode, thumbs are
> created on first view. Additionally in this mode, $wgImageLimits
> creates additional links on the image description page. This mode is
> generally more efficient (especially on page saves), and also more
> reliable in the event that there is a missing thumb.
> For information to set up 404-thumb rendering see
> https://www.mediawiki.org/wiki/Manual:Thumb.php
> --
> Brian
> On Fri, Jul 28, 2017 at 9:18 AM, Krabina Bernhard <krabina at kdz.or.at> wrote:
>> Dear MediaWiki experts,
>> I cannot really figure out the behaviour of MediaWiki regarding thumbnailing.
>> What I want to achieve is that my MediaWiki installation produces thumbnails in
>> a specified size.
>> What I did after reading through several help pages is this:
>> ---------------------------
>> # Images und Thumbnails
>> $wgThumbLimits = array( 80, 250, 390 );
>> $wgDefaultUserOptions['thumbsize'] = 1; // thumb size 250
>> $wgImageLimits = array( array( 80, 90 ), array( 800, 600 ), array( 1280, 1024 )
>> );
>> $wgDefaultUserOptions['imagesize'] = 2; // image size 800, 600
>> ---------------------------
>> In my opinion this should guarantee that for every image uploaded, there is an
>> 80, 250 and 390px sized thumbnail. In many cases this is true, but there are
>> some cases were I can find a 100px thumbnail, but no 80px thumbnail.
>> If I understand it correctly, this can perfectly be the case if any user sets
>> his/her preference to 100px. I don't mind so much extra sizes to be produced,
>> but I want to make sure that a 80px thumbnail is there.
>> Maybe in the cases where it is not present the images were uploaded before the
>> above mentioned setting was made? But how can I get the wiki to redo thumbnails
>> in my desired size?
>> cheers,
>> Bernhard
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