main.dart

//Add delete widget
Stack(
  children: <Widget>[
    InkWell(
      onTap: () => _onPhotoClicked(index - 1),
      child: Container(
        margin: EdgeInsets.all(5),
        height: 100,
        width: 100,
        color: kLightGray,
        child: source == PhotoSource.FILE
            ? Image.file(image)
            : Image.network(_photosUrls[index - 1]),
      ),
    ),
    Visibility(
      visible: _photosStatus[index - 1] == PhotoStatus.LOADING,
      child: Positioned.fill(
        child: SpinKitWave(
          size: 25,
          color: Colors.white,
        ),
      ),
    ),
    Visibility(
      visible: _photosStatus[index - 1] == PhotoStatus.ERROR,
      child: Positioned.fill(
        child: Icon(
          MaterialIcons.error,
          color: kErrorRed,
          size: 35,
        ),
      ),
    ),
    Positioned.fill(
      child: Container(
        padding: EdgeInsets.all(6),
        alignment: Alignment.topRight,
        child: DeleteWidget(
          () => _onDeleteReviewPhotoClicked(index - 1),
        ),
      ),
    )
  ],
);

//Add listener
Future<bool> _onDeleteReviewPhotoClicked(int index) async {
  if (_photosStatus[index] == PhotoStatus.LOADED) {
    _photosUrls.removeAt(index);
  }
  _photos.removeAt(index);
  _photosStatus.removeAt(index);
  _photosSources.removeAt(index);
  _galleryItems.removeAt(index);
  setState(() {});
  return true;
}