This script orders your jpeg files by adding a prefix number to each file based on the EXIF creation date. It can be run recursively. It ask a confirmation before making any changes.

jpeg-sort.py

#!/usr/bin/python
# -*- coding: iso-8859-1 -*-
__version__ = "$Revision: 0.1 $"
__author__ = "Pierrick Terrettaz"
__date__ = "2007-08-15"

import sys, os
import popen2
import pprint

def usage():
    print "%s [option] dir [dir1 [dir n]]" % os.path.basename(sys.argv[0])
    print "Options"
    print "  -h print this help"
    print "  -r rename file recursively"
    print "\nThis script orders your jpeg files by adding "
    print "a prefix number to each file based on the EXIF "
    print "creation date. It can be run recursively. "
    print "It ask a confirmation before making any changes."
    

def formatNumber(num, count):
    s = ""
    if count < 10:
        return s + "%s" % num
    else:
        numLen = len("%s" % num)
        countLen = len("%s" % count)
        if numLen >= countLen:
            s += formatNumber(num, count/10)
        else:
            s += "0" + formatNumber(num, count/10)
    return s

def check_tools():
    valid_os = ['posix']
    try:
        valid_os.index(os.name)
    except:
        print "supported os: ",
        pprint.pprint(valid_os)
        sys.exit(1)
    
    commands = ['exiftool', 'awk', 'xargs']
    missing = []
    for c in commands:
        r, w = popen2.popen2('which %s' % c)
        ret = r.readline()[:-1]
        r.close()
        w.close()
        if ret == '':
            missing.append(c)
    if len(missing) > 0:
        print "missing programs: ",
        pprint.pprint(missing)
        sys.exit(1)

def search_files(directory, paths, recursive):
    if os.path.exists(directory) and os.path.isdir(directory):
        for f in os.listdir(directory):
            path = os.path.sep.join((directory, f))
            if os.path.isfile(path) and f.lower().endswith('.jpg'):
                try:
                    paths.index(path)
                except:
                    paths.append(path)
            elif recursive and os.path.isdir(path):
                search_files(path, paths, recursive)

if __name__ == '__main__':
    
    if len(sys.argv) == 1 or sys.argv[1] == '-h':
        usage()
        sys.exit(1)

    check_tools()
    paths = []
    recursive = sys.argv[1] == '-r'
    if recursive:
        args = sys.argv[2:]
    else:
        args = sys.argv[1:]
        
    for i in args:
        search_files(i, paths, recursive)
        
    
    r, w = popen2.popen2(
        'xargs -I{} exiftool -f -DateTimeOriginal {} \
         | grep Original | awk {\'print $4 " " $5\'}')
    for p in paths:
        w.write(p+'\n')
    w.close()
    
    tmp = []
    i = 0
    for l in r.readlines():
        date_exif = l[:-1]
        if date_exif != ': -':
            tmp.append((date_exif, paths[i]))
        i += 1
        
    r.close()
    paths = tmp
    paths.sort()
    
    i = 1
    size = len(paths)
    print "%d files will be renamed, continue ? [y/n] " % size,
    choice = sys.stdin.readline()[:-1]
    if choice.lower() == 'y':
        for date, p in paths:
            f = os.path.basename(p)
            d = os.path.dirname(p)
            old_file = os.path.sep.join((d, f))
            try:
                idx = f.index('_')
                int(f[:idx]) # check if the predfix is an number
                f = f[idx+1:]
            except: pass
                        
            new_file = "%s%s%s_%s" % (d, os.path.sep, formatNumber(i, size), f)
            os.rename(old_file, new_file)
            i += 1
            
    print "%d files renamed" % (i-1)