add 'jpg' default content type

Author: Steve Canny

docx.py

@@ -215,7 +215,14 @@ def contenttypes():
     for part in parts:
         types.append(makeelement('Override',nsprefix=None,attributes={'PartName':part,'ContentType':parts[part]}))
     # Add support for filetypes
-    filetypes = {'rels':'application/vnd.openxmlformats-package.relationships+xml','xml':'application/xml','jpeg':'image/jpeg','gif':'image/gif','png':'image/png'}
+    filetypes =\
+        { 'gif'  : 'image/gif'
+        , 'jpeg' : 'image/jpeg'
+        , 'jpg'  : 'image/jpeg'
+        , 'png'  : 'image/png'
+        , 'rels' : 'application/vnd.openxmlformats-package.relationships+xml'
+        , 'xml'  : 'application/xml'
+        }
     for extension in filetypes:
         types.append(makeelement('Default',nsprefix=None,attributes={'Extension':extension,'ContentType':filetypes[extension]}))
     return types