bar_width = 35
     background_color = '#444'
     author_color = '#444'
+    default_background = get_resource('res/background.jpg')
+    format = 'JPEG'
 
     epochs = {
         u'Starożytność': 0,
             bg_src = urlopen(book_info.cover_url)
             self.background_img = StringIO(bg_src.read())
             bg_src.close()
+        else:
+            self.background_img = self.default_background
 
     def pretty_author(self):
         return self.author.upper()
 
         if options.verbose:
             print input_filename
 
-        output_filename = os.path.splitext(input_filename)[0] + '.png'
+        output_filename = os.path.splitext(input_filename)[0] + '.jpg'
 
         doc = WLDocument.from_file(input_filename)
         WLCover(doc.book_info).save(output_filename)