Please help!! How do you upload a pic through URL??

I am trying to add a picture to the “About Me” section of my page. I have the Amadeus theme. Where is a URL from a picture supposed to come from? When I try adding a link to a photo that already exists on the internet, like from Facebook, the image does not load. How do I do this correctly and why can’t I just upload an image from my files? Does this mean that I can only add pictures that already exist on the internet? My site is http://www.whosthatdrifter.com