On my Mac OS X 10.10.1 machine, when I enter the URL into a Safari window, nothing is returned in the current window (check the Page Source), and a new window appears with a JPG image. You will need to access the URL that opens the JPG image directly.
The url you included does some 301 redirects to get to the final url. The insert from url step doesn't follow redirects, so the first url loads, returns some valid headers ( which you can't access ) and that's it, it's all done.
A web browser will go to the new page identified in the headers, but the fmp step won't. It will be worth submitting a feature request for this, or asking for access to the headers instead.