Icon for PhotoCollage. Fixes #1191

Icon for PhotoCollage, issue #1191
![photocollage48](https://cloud.githubusercontent.com/assets/7050624/5480722/3b5d613c-8649-11e4-99ae-9e2291d8d61f.png)
![photocollage32](https://cloud.githubusercontent.com/assets/7050624/5480724/3feb3ddc-8649-11e4-965c-2c6de6758297.png)