I have been a user of the open source software greenshot for years it is a great program for screenshots by far the best for my needs the rest simply were either too bloated or too clunky.
So what you can do is upload the file as an attachment and place image file inline. But doing it the way you are doing it is likely better as it saves the website from traffic resulting from hosting the picture I suppose....
Where I buy my ESP8266 boards from... (Banggood)