I want to share this little (openFL) extension with you.
With this extension you can send an actor (the bitmapdata of an actor) as a png file to the server.
With the screenshot extension you can save the screenshot of a game on the server and send the link to facebook withe the facebook extention.
The block:
send PNG from [actor] to Url [http://myserver.com/savepng.php] with filename [myscreenshot.png]
You will need a serverside script (see example in readme.txt)
Tested on android, ios, flash (don't forget the crossdomain.xml).
Have fun