comes with a utility 'ppmtoy4m' that can convert PPM-format images into a yuv4mpeg stream, which can be piped into mpeg2enc to create an .mpg from them. Check out the Mjpeg HOWTO
for more information.
To convert your images to PPM, you can use ImageMagick
. For a directory full of jpegs, something like this:
for file in *.jpg
convert $file -depth 8 $file.ppm
If you enter the lines above in your terminal window (one after the other, pressing <enter> at the end of each line) it'll process all the .jpg files in the current directory. You can then use ppmtoy4m on them:
cat *.ppm | ppmtoy4m | mpeg2enc -o output.mpg
You may need to include other options to ppmtoy4m, such as what framerate to use, how many frames to encode, etc.