Thanks to Silvan [1] who mentioned that feature of mplayer. Quite easy that way, to get certain images out of a movie. mplayer is available for several operating systems [2].
mplayer -frames 1 -vo jpeg outdir=/tmp:quality=75 path/to/movie.mov
Who is going to make mplayer a PHP PECL extension? đ
[1] http://blog.var.cc/p43.html
[2] http://www.mplayerhq.hu/homepage/design6/projects.html
Update: Some nice tips by Ben Edgington [3] using mplayer, imagemagick, mplex etc.
[3] http://www.edginet.org/techie/linux/canon_movies.html