You can find some art assets in the Green Room - at www.thegreenroom.sessionslive.com - which is our hub of information and resources for Artists! More specifically, you can download our assets pack by following the Google Drive link directly by clicking here.
The assets pack is simply some art, pictures, and fonts that you can use when creating your post and editing your images. This is done by "self-service", which means that you're going to be the one building your own posts. At the moment, Sessions doesn't offer the service of creating the posts in your stead.