How to reference images in /docs?

[Bernd Mathiske]

When adding/editing MD documentation in the “docs” folder of the Mesos 
workspace, I’d like to add some graphics. I have found two pre-existing 
approaches. 

1. In mesos-architecture.md, we find:
    ![Mesos 
Architecture](http://mesos.apache.org/assets/img/documentation/architecture3.jpg)

2. In external-containerizer.md, we find:
     ![Recovery Scheme](images/ec_recover_seqdiag.png?raw=true)

In case of #1 the images turn up on the Apache Mesos web page, eventually, but 
not until that has been pushed. In case of #2 you can point your MD renderer at 
your local Mesos workspace and they show up then.

Is there a better third path that displays the images in multiple situations? 
If not, am I assuming correctly that #1 is preferred?

Bernd