A bash script using ffmpeg to generate video posters
Mac OS X bash script - Requires ffmpeg to be installed
Place the script in your main video folder.
cd into the folder and run . generate_posters.sh
The script prompts you for a destination folder.
Type it in and hit return.
The script will then create a matching directory structure in the destination folder and open all videos with ffmpeg to generate a .jpg of the first frame.
The file name will be in the format "poster_{index}.jpg"
Check binpress.com, they have a very detailed article about it.