PICON is a file that type that is associated with an image or an icon. It stands for Personal icon file. It is very helpful in the world of multi-media. Can be very useful when you have to choose something just from a preview of it.
It displays a small icon of the channel in the EPG (Electronic Photo Guide). This is associated with a channel as a small preview. Can also be described as the logo of the application. It represents what channel you are looking at.