Instagrim  is an example web app using Cassandra as a back end.   The app allows picture uploads, creates a thumbnail and 
a  B/W version of the picture.

See Keyspaces.java for a definition of the keyspaces.
CassandraHosts manages the connections. 
The code uses org.imgscalr.Scalr for image manipulation
It is a Netbeans maven based project.

As of September 2014 this is a work in process. More needs to be done. 

The code is used as an example for AC32007, School of Computing, Univeristy of Dundee.  I know things are still not right !