diff --git a/src/PIL/IcnsImagePlugin.py b/src/PIL/IcnsImagePlugin.py
index 21fd558f2..7c1bd5882 100644
--- a/src/PIL/IcnsImagePlugin.py
+++ b/src/PIL/IcnsImagePlugin.py
@@ -353,6 +353,11 @@ 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
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:]))