Comment 6 for bug 51569

The limit only applies to image formats, as Nautilus does not actually thumbnail videos (gnome-video-thumbnailer, which is just a special way of calling Totem, does). The limit imposed by Nautilus will never apply to videos, since it does not make sense to do so; thumbnailing a video only renders one frame of the video about 30 seconds in, whereas thumbnailing images requires reading the entire image file and then scaling it down to thumbnail size.