border radius of image not curving

I am returning photos in a grid view, and according to docs, this is the correct method to curve the edges of the photos, instead of them being 90 degree angles.

However, when I test out the application, the angles are not curving.

Any thoughts?

GridView.count(
                          shrinkWrap: true,
                          crossAxisCount: 2,
                          childAspectRatio: (50 / 80),
                          padding: const EdgeInsets.all(3.0),
                          children:
                              List.generate(widget.imageArray.length, (index) {
                            return Container(
                                child: Image.file(widget.imageArray[index]),
                                decoration: BoxDecoration(
                                    borderRadius: BorderRadius.all(
                                        Radius.circular(100.0))))

Read more here: https://stackoverflow.com/questions/66501287/border-radius-of-image-not-curving