How set an Icon in a local notification properly

Hi, i’m searching different ways of put icons with the local notifications.

I achieve this creating a new folder in platform/drawable and creating a PNG file, then i do icon: ‘nameicon’ and it works, but i have a problem…

The icon it’s set tiny and it’s minimified by a circle with another color (some kind of blue or grey)… How i can see the entire icon without that?