Notifications in the notification drawer appear in two main visual styles, normal view and big view. The big view of a notification only appears when the notification is expanded. This happens when the notification is at the top of the drawer, or the user clicks the notification.

Notifications in the notification drawer appear in two main visual styles, normal view and big view. The big view of a notification only appears when the notification is expanded. This happens when the notification is at the top of the drawer, or the user clicks the notification.
Big views were introduced in Android 4.1, and they're not supported on older devices.
The image will be loaded from URL or as a drawable id or from assets folder, it should be 2:1 aspect ratio not to be cropped by Android.

To define a Big Picture image, add the following payload fields :

Payload field key: bigPicture
Type
: string
Value
: drawable id, image from assets folder without extension or image URL
Only png, jpg and png are supported.

{"payload":{"bigPicture":"http://vignette3.wikia.nocookie.net/masseffectitalia/images/e/e8/Cdx_palaven_512x256.jpg/revision/latest?cb=20121203161621"}}
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