getImageFileFromAssets method
Copies the asset at assetPath to the device's temporary directory and
returns the resulting File.
The file is always written as temp_image.png in the temporary directory,
so it will be overwritten on subsequent calls.
Implementation
Future<File> getImageFileFromAssets(String assetPath) async {
final byteData = await rootBundle.load(assetPath);
final dir = await getTemporaryDirectory();
final file = File('${dir.path}/temp_image.png');
await file.writeAsBytes(byteData.buffer.asUint8List());
return file;
}