- Yes, facebook prevents you from using images from it's CDN in posts, shares etc.
- Yes. You can use a intermediate page that takes the CDN image and copy it on-the-fly. My script does exactly that (see below)
- There is no official documentation regarding the use of CDN images.
http://sportplatform.sportengland.org/videos/image.php?src=http://a8.sphotos.ak.fbcdn.net/hphotos-ak-snc6/602487_10150174597139971_1671360825_n.jpg
Basic structure is http://sportplatform.sportengland.org/videos/image.php?src={image url}
. You can add an image into the URL, include one on Facebook's CDN. However, this is a commercial script that I created so I don't advise on using it directly. Think of it more like a proof of concept.