It seems that the images displayed in the web interface are all saved in the mongodb in its GridFS. Also after a job is deleted the image files (PNG and PDF) are not removed from the GridFS. As a consequence the database keeps growing over time. For instance, my database is now 22 GB in size, after only 2000 jobs. In the DB, the fs.chunks collection uses 21 GB. From the information in fs.files I can see that most of them are not really worth keeping.
Is it possible to provide a database cleaning function? Or even better, is it possible to save the intermediate files in the job directory so that they can be managed as regular files?