Some time ago I tried to use the background rendering to get the list of png images. Now, using it on a test movie doesn't seem to affect achivied frames (which always remain 14 fps dropping to 4 fps with plugins). But the most disconcerting thing is that you do not create still images: the folder I had indicated remains empty, even in /tmp I can't find anything. In short, background rendering doesn't seem to work on my system (as if that wasn't enough!). I've tried both to enable the render farm in localhost and to disable it. Same result. On the arch forum I don't find any problem with the graphic libraries, the versions are the same. The only thing that comes to mind is a formatting of the notebook and restart from 0. But I'll wait until after finishing the translations for the website.