refactor image.py

image.py

@@ -61,4 +61,5 @@
 
         if not value:
             return ""
+        tmp = image(value)
 
@@ -64,5 +65,2 @@
 
-        content = base64.b64decode(value)
-        mimetype = guess_mimetype(content)
-
-        return "data:{};base64,{}".format(mimetype, value.decode("ascii"))
+        return "data:{};base64,{}".format(tmp["mime-type"], tmp["body"])