djangocms / djangocms-filer: 500 server error: failed to generate icons for file

This is a nasty error, because django-filer just returns this error message in json format when uploading a file via FilerImageField or the djangocms-filer admin interface.

In order to find out the true reason behind this, set the following env vars to true:


FILER_DEBUG will return a real python exception in the response to the async request that handles the file upload.

In my case, the true error was: decoder jpeg not available which I handled via

That helped!