import os

max_mtime = 0
for dirname,subdirs,files in os.walk('/Users/raynerd/weatherstuff/pictures/'):
    for fname in files:
        full_path = os.path.join(dirname, fname)
        mtime = os.stat(full_path).st_mtime
        if mtime > max_mtime:
            max_mtime = mtime
            max_file = fname

def get_digits(str1):
    print str1
    print str1
    c = ""
    for i in str1:
        if i.isdigit():
            c += i
    return c

latest_photo_number = get_digits(str(max_file))

# latest_photo_number holds the number of the last edited picture.