Here's an example of a file that's encoded
http://c.mmcdn.net/game/season.2.7.1/1. ... _convo.xml
You can right click this link and "Save as" and rename the extention to PNG. It should look like this:

Decompiling their flash game I stumbled upon the decryption algorithm (attached). Looks really intriguing. But, it's ActionScript, I suppose since it's so similar to EcmaScript it could be translated to that OR, I don't know if it could be something that could be programmed in QuickBMS. Either way, doesn't look like a trivial task to do.
Opinions? Some advice would be really appreciated. I did try to understand the algorithm a bit, looks complex to me with byteshifts and AND operators, bitmap rotations, etc. help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/operators.html