As of Flutter beta 2, assets are stored in the native asset folder,
and are accessed on the native side using Android’s AssetManager:

val

flutterAssetStream

assetManager

open

"flutter_assets/assets/my_flutter_asset.png"

As of Flutter beta 2, Flutter still cannot access native resources,
nor it can access native assets.

To add a new image asset called my_icon.png to our Flutter project,
for example, and deciding that it should live in a folder we
arbitrarily called images, you would put the base image (1.0x)
in the images folder, and all the other variants in sub-folders
called with the appropriate ratio multiplier:

Next, you’ll need to declare these images in your pubspec.yaml file:

assets

images/my_icon.jpeg

You can then access your images using AssetImage: