diff --git a/PIL/ImageMorph.py b/PIL/ImageMorph.py
index 4847594f6..748ecdb61 100644
--- a/PIL/ImageMorph.py
+++ b/PIL/ImageMorph.py
@@ -156,10 +156,10 @@ class LutBuilder(object):
 #        print '--'
 
         # compile the patterns into regular expressions for speed
-        for i in range(len(patterns)):
-            p = patterns[i][0].replace('.', 'X').replace('X', '[01]')
+        for i, pattern in enumerate(patterns):
+            p = pattern[0].replace('.', 'X').replace('X', '[01]')
             p = re.compile(p)
-            patterns[i] = (p, patterns[i][1])
+            patterns[i] = (p, pattern[1])
 
         # Step through table and find patterns that match.
         # Note that all the patterns are searched. The last one
diff --git a/PIL/PalmImagePlugin.py b/PIL/PalmImagePlugin.py
index 4f415ff7c..d02839bdf 100644
--- a/PIL/PalmImagePlugin.py
+++ b/PIL/PalmImagePlugin.py
@@ -80,13 +80,12 @@ _Palm8BitColormapValues = (
 
 # so build a prototype image to be used for palette resampling
 def build_prototype_image():
-    image = Image.new("L", (1, len(_Palm8BitColormapValues),))
+    image = Image.new("L", (1, len(_Palm8BitColormapValues)))
     image.putdata(list(range(len(_Palm8BitColormapValues))))
     palettedata = ()
-    for i in range(len(_Palm8BitColormapValues)):
-        palettedata = palettedata + _Palm8BitColormapValues[i]
-    for i in range(256 - len(_Palm8BitColormapValues)):
-        palettedata = palettedata + (0, 0, 0)
+    for colormapValue in _Palm8BitColormapValues:
+        palettedata += colormapValue
+    palettedata += (0, 0, 0)*(256 - len(_Palm8BitColormapValues))
     image.putpalette(palettedata)
     return image
 
diff --git a/PIL/TiffImagePlugin.py b/PIL/TiffImagePlugin.py
index 3af38832d..52e04654c 100644
--- a/PIL/TiffImagePlugin.py
+++ b/PIL/TiffImagePlugin.py
@@ -1246,12 +1246,12 @@ class TiffImageFile(ImageFile.ImageFile):
                 a = None
 
             else:
-                for i in range(len(offsets)):
+                for i, offset in enumerate(offsets):
                     a = self._decoder(rawmode, l, i)
                     self.tile.append(
                         (self._compression,
                             (0, min(y, ysize), w, min(y+h, ysize)),
-                            offsets[i], a))
+                            offset, a))
                     if DEBUG:
                         print("tiles: ", self.tile)
                     y = y + h