I've been using Crunchbang (Debian based) for a while without problems, but yesterday I decided to make a cleanup. I deleted lots of files, and uninstalled some programs. I also uninstalled everything related with gstreamer because I wasn't using it. But it was being used to create video thumbnails.
I've searched in the web, and decided to install ffmpegthumbnailer, because it seems fastes than gstreamer. I killed thunar, and opened again, but no new thumbnails. I rebooted, and the same. I deleted all the thumbnails in the folder ~/.thumbnails/normal, and the thumbnails for every type of file were created again, but not for videos.
I found the folder /usr/share/thumbnailers, with evince instructions, but I need to know every video MIME type. If this is the way to add a new thumbnailer, how can I know every video mime type? If this is not the way, which is the way in Crunchbang?

Linux is not Windows. There is no need to "delete cruft and bloatware to make your system run properly" as one might do on purchasing a typical consumer Windows machine. In fact, many beginner users break their systems thinking they know better than the developer/experts. You are lucky you are only missing thumbnails!

My advice is to ask on the CrunchBang forums and you will probably have a good answer within 15 minutes. Those guys are on the ball!

I think there is a package called something like 'crunchbang-desktop' that you can reinstall to get back to the developer's recommended configuration (but I don't know for sure since I am not a #! user). If all else fails, a fresh reinstall takes less than 20 minutes.

I know is not necessary to unistall things as in Windows, but I do it once in a while to remove configurations and non-uninstalled parts of what I installed and uninstalled. Even if it doesn't slow the system, I like clean things, I'm a bit fussy.

I asked on Crunchbang forums a few days ago and nobody answered

But just today I had an idea. I searched on the logs what packages I uninstalled, and reinstalled them. And it worked .

Thank you anyway.