gistfile1.python

#!/usr/bin/env python

import sys
import pyexiv2
import os.path

def main():
    if len(sys.argv) < 2:
        print "Specify file to examine, please."

    filename = sys.argv[1]

    meta = pyexiv2.ImageMetadata(filename)
    meta.read()

    tn = pyexiv2.exif.ExifThumbnail(meta)

    if tn.data == "":
        print "No thumbnail found."
        return


    (path, fn) = os.path.split(filename)
    thumbfilename = os.path.join(path, "tn_" + fn)

    tn.write_to_file(thumbfilename)

if __name__ == '__main__':
    main()