I've just posted two answers from guides providing good answers. On both of them are images explaining the steps.
I can't find the reference. But somewhere on Ask Ubuntu it was said that it's better to copy a guide than to link them, since you can never know when the linked is going to be offline.
With that philosophy I thought that by including a image by selecting a image-URL it would copy it over from the original guide and link that.
Now this isn't the case. By adding a image by URL from another page you will it hotlink the image from the original source. If the image changes or the server of this page goes down, the image-link will be broken.
What is the recommended way to avoid hotlinking images?