I am creating a screen for updating place details, where admin can view and delete existing images for that place or upload new images

This is my GridView.builder: [dart file]

GridView.builder(
                shrinkWrap: true,
                itemCount: _newImages.length + provider.getImagesForPlace(widget.place.id).length,
                gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 3,
                  crossAxisSpacing: 4.0,
                  mainAxisSpacing: 4.0,
                ),
                itemBuilder: (BuildContext context, int index) {
                  if (index < _newImages.length) {
                    // Render new images
                    return Stack(
                      fit: StackFit.expand,
                      children: [
                        Image.file(
                          _newImages[index],
                          fit: BoxFit.cover,
                        ),
                        Positioned(
                          right: 5,
                          top: 5,
                          child: GestureDetector(
                            onTap: () {
                              setState(() {
                                _newImages.removeAt(index);
                              });
                            },
                            child: const Icon(
                              Icons.cancel,
                              color: Colors.red,
                            ),
                          ),
                        ),
                      ],
                    );
                  } else {
                    // Render existing images
                    final existingImages = provider.getImagesForPlace(widget.place.id);
                    final existingImageIndex = index - _newImages.length;
                    return existingImages.isEmpty
                        ? Container() // Empty container if no existing images
                        : Image.memory(existingImages[existingImageIndex].bytes);
                  }
                },
              ),

Now, in above code:
1. _newImages is defined as:

final List<File> _newImages = [];

2. a. getImagesForPlace function is from where downloaded images can be retrieved. provider is used for state management, this how the function is :

List<MemoryImage> getImagesForPlace(String placeId) {
  return _placeImages[placeId] ?? [];
}

b. _placeImages is defined as:

final Map<String, List<MemoryImage>> _placeImages = {};

where downloaded images are stored

Now, I am getting error in GridView at itemCount

Error: The argument type 'num' can't be assigned to the parameter type 'int?'.
                itemCount: _newImages.length + provider.getImagesForPlace(widget.place.id).length