diff --git a/kcc/comic2ebook.py b/kcc/comic2ebook.py
index ce80873..f0f80ec 100755
--- a/kcc/comic2ebook.py
+++ b/kcc/comic2ebook.py
@@ -35,6 +35,7 @@ from xml.dom.minidom import parse
 from uuid import uuid4
 from slugify import slugify as slugifyExt
 from PIL import Image
+from hashlib import md5
 try:
     from PyQt5 import QtCore
 except ImportError:
@@ -45,7 +46,19 @@ from . import cbxarchive
 from . import pdfjpgextract
 
 
+def md5Checksum(filePath):
+    with open(filePath, 'rb') as fh:
+        m = md5()
+        while True:
+            data = fh.read(8192)
+            if not data:
+                break
+            m.update(data)
+        return m.hexdigest()
+
+
 def buildHTML(path, imgfile, imgfilepath):
+    imgfilepath = md5Checksum(imgfilepath)
     filename = getImageFileName(imgfile)
     if filename is not None:
         if "Rotated" in theGreatIndex[imgfilepath]:
@@ -671,7 +684,6 @@ def slugify(value):
 
 
 def sanitizeTree(filetree):
-    global theGreatIndex
     chapterNames = {}
     for root, dirs, files in os.walk(filetree, False):
         for name in files:
@@ -687,8 +699,6 @@ def sanitizeTree(filetree):
                 key = os.path.join(root, name)
                 if key != newKey:
                     os.rename(key, newKey)
-                    theGreatIndex[newKey] = theGreatIndex[key]
-                    del theGreatIndex[key]
         for name in dirs:
             if name.startswith('.'):
                 os.remove(os.path.join(root, name))
@@ -702,14 +712,6 @@ def sanitizeTree(filetree):
                 key = os.path.join(root, name)
                 if key != newKey:
                     os.rename(key, newKey)
-                    theGreatIndexTmp = theGreatIndex.copy()
-                    for keyI in theGreatIndex:
-                        if key in keyI:
-                            newKeyI = keyI.replace(key, newKey)
-                            if newKeyI != keyI:
-                                theGreatIndexTmp[newKeyI] = theGreatIndexTmp[keyI]
-                                del theGreatIndexTmp[keyI]
-                    theGreatIndex = theGreatIndexTmp.copy()
     return chapterNames
 
 
diff --git a/kcc/image.py b/kcc/image.py
index edde36d..b3016cd 100755
--- a/kcc/image.py
+++ b/kcc/image.py
@@ -21,10 +21,22 @@ __copyright__ = '2012-2013, Ciro Mattia Gonano <ciromattia@gmail.com>, Pawel Jas
 __docformat__ = 'restructuredtext en'
 
 import os
+from hashlib import md5
 from functools import reduce
 from PIL import Image, ImageOps, ImageStat, ImageChops
 
 
+def md5Checksum(filePath):
+    with open(filePath, 'rb') as fh:
+        m = md5()
+        while True:
+            data = fh.read(8192)
+            if not data:
+                break
+            m.update(data)
+        return m.hexdigest()
+
+
 class ProfileData:
     def __init__(self):
         pass
@@ -146,7 +158,7 @@ class ComicPage:
                 else:
                     filename += ".jpg"
                     self.image.save(filename, "JPEG", optimize=1)
-                return [filename, flags]
+                return [md5Checksum(filename), flags]
             else:
                 return None
         except IOError as e: