Ever wonder how many of the movie review sites generate a series of snapshots such as the one below?
Answer: Video Thumbnails Maker 18.104.22.168
Very simple to use, just click Add Files and press Start and the thumbnail file will be generated in the same folder where the media file is.
If all you want is to do a automatic jpg or gif capture of a video file (the time interval can be set to reduce HHD space usage), Video to Picture is one good alternative. Note this is a paid software but occasionally, you may be able to get it from Giverawayoftheday.com which is what your truly got it for free
Another interesting way to create a thumbnail for your video media file is using vlc but it is technically challenging, i have not tried it but the link is here.