diff --git a/src/PIL/IcnsImagePlugin.py b/src/PIL/IcnsImagePlugin.py
index 5c5bd7cf9..7c1bd5882 100644
--- a/src/PIL/IcnsImagePlugin.py
+++ b/src/PIL/IcnsImagePlugin.py
@@ -353,13 +353,18 @@ if sys.platform == 'darwin':
 
 
 if __name__ == '__main__':
+
+    if len(sys.argv) < 2:
+        print("Syntax: python IcnsImagePlugin.py [file]")
+        sys.exit()
+
     imf = IcnsImageFile(open(sys.argv[1], 'rb'))
     for size in imf.info['sizes']:
         imf.size = size
         imf.load()
         im = imf.im
         im.save('out-%s-%s-%s.png' % size)
-    im = Image.open(open(sys.argv[1], "rb"))
+    im = Image.open(sys.argv[1])
     im.save("out.png")
     if sys.platform == 'windows':
         os.startfile("out.png")
diff --git a/src/PIL/ImageShow.py b/src/PIL/ImageShow.py
index bf8c67eb5..fdd739920 100644
--- a/src/PIL/ImageShow.py
+++ b/src/PIL/ImageShow.py
@@ -186,5 +186,9 @@ else:
         register(XVViewer)
 
 if __name__ == "__main__":
-    # usage: python ImageShow.py imagefile [title]
+
+    if len(sys.argv) < 2:
+        print("Syntax: python ImageShow.py imagefile [title]")
+        sys.exit()
+
     print(show(Image.open(sys.argv[1]), *sys.argv[2:]))
diff --git a/src/PIL/SpiderImagePlugin.py b/src/PIL/SpiderImagePlugin.py
index 5e5dde5a6..b65f181d8 100644
--- a/src/PIL/SpiderImagePlugin.py
+++ b/src/PIL/SpiderImagePlugin.py
@@ -48,9 +48,7 @@ def isInt(f):
             return 1
         else:
             return 0
-    except ValueError:
-        return 0
-    except OverflowError:
+    except (ValueError, OverflowError):
         return 0
 
 iforms = [1, 3, -11, -12, -21, -22]
@@ -286,7 +284,7 @@ Image.register_save(SpiderImageFile.format, _save_spider)
 
 if __name__ == "__main__":
 
-    if not sys.argv[1:]:
+    if len(sys.argv) < 2:
         print("Syntax: python SpiderImagePlugin.py [infile] [outfile]")
         sys.exit()
 
@@ -295,10 +293,6 @@ if __name__ == "__main__":
         print("input image must be in Spider format")
         sys.exit()
 
-    outfile = ""
-    if len(sys.argv[1:]) > 1:
-        outfile = sys.argv[2]
-
     im = Image.open(filename)
     print("image: " + str(im))
     print("format: " + str(im.format))
@@ -307,7 +301,9 @@ if __name__ == "__main__":
     print("max, min: ", end=' ')
     print(im.getextrema())
 
-    if outfile != "":
+    if len(sys.argv) > 2:
+        outfile = sys.argv[2]
+
         # perform some image operation
         im = im.transpose(Image.FLIP_LEFT_RIGHT)
         print(