One of my recent projects required me to convert a time-lapse video of a microscope slide to a sequence of JPEGs so I could analyze these JPEGs using imageJ. To accomplish the conversion I used my iMac running OS X and FFmpeg, a freely available image and video conversion program. I ran the following command in a terminal window from within the directory containing my time-lapse video to perform the conversion.

ffmpeg -i myVideo.mov -s 640x480 %04d.jpg

Change the video file name to whatever your video is called, and ensure the resolution matches your video’s resolution (mine was 640 pixels wide by 480 pixels high). The %04d portion of the command ensures that the .jpg files created are numbered sequentially and the file names are padded with zeros (e.g., 0001.jpg instead of 1.jpg) so they are sorted correctly by unix.

Good luck.