Hack This Site! - Programming 2

#!/usr/bin/env python
#===================================================================================
#
#         FILE: HTS-Programming-02.py
#
#        USAGE: HTS-Programming-02.py
#
#  DESCRIPTION: This script is for level 2 challenge in HackThisSite
#               programming missions.
#  _____  _              _         _____  _                     _____     _____
# |   __||_| _____  ___ | | ___   |  _  || | ___  ___    ___   |   __|   |  _  |
# |__   || ||     || . || || -_|  |   __|| || .'||   |  |___|  |__   | _ |   __|_
# |_____||_||_|_|_||  _||_||___|  |__|   |_||__,||_|_|         |_____||_||__|  |_|
#                  |_|
#
#===================================================================================

from PIL import Image

img_file = Image.open("/root/HTS/code.png")
img_width, img_height = img_file.size
img_pixel = img_file.load()
preposition=0
morse_code=""
answer=""

char_morse_dict={
'A':'.-','B':'-...','C':'-.-.','D':'-..','E':'.','F':'..-.',
'G':'--.','H':'....','I':'..','J':'.---','K':'-.-','L':'.-..',
'M':'--','N':'-.','O':'---','P':'.--.','Q':'--.-','R':'.-.',
'S':'...','T':'-','U':'..-','V':'...-','W':'.--','X':'-..-',
'Y':'-.--','Z':'--..','0':'-----','1':'.----','2':'..---','3':'...--',
'4':'....-','5':'.....','6':'-....','7':'--...','8':'---..','9':'----.',
'.':'.-.-.-',',':'--..--','?':'..--..',"'":'.----.','/':'-..-.','(':'-.--.-',
')':'-.--.-',':':'---...',';':'-.-.-.','=':'-...-','+':'.-.-.','-':'-....-',
'_':'..--.-','"':'.-..-.','$':'...-..-','':''
}

# fetch ASCII code from image
for y_point in range(img_height) :
    for x_point in range(img_width) :
        if img_pixel[x_point, y_point] == 1 :
            # convert ASCII code to "dits" and "dahs" in morse code
            symbol = chr(x_point + 100 * y_point - preposition)

            if symbol != ' ' :
                morse_code += symbol
            else :
                # decode morse code to character
                char = [key for key, value in char_morse_dict.iteritems() if value == morse_code][0]
                answer += char
                morse_code = ""

            preposition=x_point + 100 * y_point
# bye bye
print answer