Page MenuHomePhabricator

Recently uploaded files without thumbnails in Commons categories
Closed, DuplicatePublicBUG REPORT


List of steps to reproduce

  • Upload a file to Commons
  • Add a category
  • Look into category (thumbnails of files)

What happens?:
Some (but not all) recently uploaded files don't show thumbnails, but only the filename. I've been registering this behaviour for more than a year.

What should have happened instead?:
The file thumbnails should appear in the categories.


some_thumbnails.PNG (486×796 px, 136 KB)

These are mine files uploaded by Pattypan, doesn't matter if I'm logged in/out, browser, OS...

I assume that it can be caused by some caching problems. After purging the server cache, the thumbnails would usually appear.

Event Timeline

@Draceane Hi, could you please provide a link where exactly this can be seen? Thanks.

JoKalliauer subscribed.

@Aklapper The screenshot might be from or similar.

@Draceane : There are two possible reasons.

  1. You have a slow internet connection and those files which are not already stored in your cache are not loaded, then we should change the "Status" to "Invalid"
  2. The rendering of thumbnails need some processing-time, if you encounter the problem within ~60 seconds (~90sec for SVGs) than you need to wait till the processing of thumbnail is finished. Then we should change the "Status" to "Declined".


  1. It happens on various devices with stable internet connection.
  2. It happened in next two days after upload on various devices even if the category page hadn't been visited befor (thus it couldn't be caused by device's cache).

@Draceane Sorry, that's true. The problem is that MediaWiki starts to processes images imho only on request. If you are the first requesting an image with the size 120px, MediaWiki starts processing the image. Some images might finish in time, however processing multiple images at the same time will lead to a holding stack, therefore some images are not finished.

I think the "bug" is that thumbnails with 120px is not rendered by default, on uploading.

@Draceane If you refresh the page one minute after you loaded the page the first time the images should be available? (If not, I think that not the case that might be that the server does not allow requesting of too many thumbnails at once, to avoid Denial-of-Service attacks.)