Here it says that you just put that link and character id in the image label/button http://devforum.roblox.com/t/new-image-endpoints-that-can-be-used-in-game/28182 it works with webgl3d's character but not mine. i tried a few other and its 50/50 only 50% of people show up
It seems the images don't exist on the CDN until first requested. After the first request, the CDN will get the image but it takes a few minutes.
I just tried using your userId and it works fine.
Also by CDN, I'm referring to the URL that the web API redirects to. For example, the headshot-thumbnail URL for me,
Redirects to rbxcdn.com...
The CDN URL I pasted above is not guaranteed to always work