The Bitter Tears of Petra von Kant, 1972. Six Movie Stills.

Movie still of The Bitter Tears of Petra von Kant
Movie still of The Bitter Tears of Petra von Kant at 00hh15mm.
Movie still of The Bitter Tears of Petra von Kant
Movie still of The Bitter Tears of Petra von Kant at 00hh41mm51ss.
Movie still of The Bitter Tears of Petra von Kant 00hh43mm44ss
Movie still of The Bitter Tears of Petra von Kant at 00hh43mm44ss.
Movie still of The Bitter Tears of Petra von Kant 00hh47mm
Movie still of The Bitter Tears of Petra von Kant at 00hh47mm.
Movie still of The Bitter Tears of Petra von Kant 01hh43mm16ss
Movie still of The Bitter Tears of Petra von Kant at 01hh43mm16ss.
Movie still of The Bitter Tears of Petra Von Kant 01hh54mm
Movie still of The Bitter Tears of Petra von Kant at 01hh54mm.

 

./ffmpeg -ss 01:43:40 -i "The Bitter Tears of Petra Von Kant [1972].mkv" -r 1 -t 10 -q:v 1 image%d.png

Note: "-q:v 1" denotes the image quality where "q" means quality and "1" is the value; lower values represent higher quality.

Wings of Desire, 1987. Full Movie Thumbnail Grid.

Wing of Desire thumbnails.
Complete two hour movie in thumbnails.
./ffmpeg -ss 00:00:05 -i "Wings of Desire [1987].mkv" -frames 1 -vf "select=not(mod(n\,60)),scale=200:125,tile=59x34:padding=1:color=green" -vsync 0 22out.png

The above command was not used to generate the thumbnails, but it is one tried and including here for a reference point, but future attempts require trial and error.