Make bright printing optional

showbits-thermal-printer/static/image.html

@@ -10,6 +10,9 @@
     <form method="post" enctype="multipart/form-data">
       <ol>
         <li><input type="file" name="image" /></li>
+        <li>
+          <label><input type="checkbox" name="bright" checked /> Bright</label>
+        </li>
         <li><button>Print!</button></li>
       </ol>
     </form>