I'm using the following line to add images from the internet:
! [Imagen] (http://animals.sandiegozoo.org/sites/default/files/2016-09/animals_hero_armadillo_0.jpg)
This has worked for me, but I've tried this:
! [Imagen] (~ / Usuarios / mi nombre / Escritorio / imagen_nombre.png)
to add images from my desktop and it does not work, I have not found anywhere like doing it.