message: fix image width to 1000px for email
diff: @@ -76,7 +76,7 @@ class EmailNotification(BaseNotification): # pylint: disable=too-few-public-met
  """,
  description=self._content.description or "",
  url=self._content.url,
  - img_tag='<img src="cid:{}">'.format(msgid)
  + img_tag='<img width="1000px" src="cid:{}">'.format(msgid)
  if self._content.screenshot
  else "",
  )
  