hello, when I use custom child,the image size can not be set

[z1047549075]

when the image size is small,but when I use like this:

builder: (BuildContext context, int index) {
                  return PhotoViewGalleryPageOptions(
                    imageProvider: CachedNetworkImageProvider(
                        'http://168.168.13.70:9500/dashboard/?action=accessFile&path=/.dj_data/temp/IMG_0578.HEIC-small.jpg'),
                    initialScale: PhotoViewComputedScale.contained,
                    minScale: PhotoViewComputedScale.contained * 0.8,
                    maxScale: PhotoViewComputedScale.covered * 4.1,
                  );
                }

it can be fill the box.

but,when I use customchild:

builder: (BuildContext context, int index) {
                  return PhotoViewGalleryPageOptions.customChild(
                    
                    initialScale: PhotoViewComputedScale.contained,
                    // minScale: 1.0,
                    // maxScale: PhotoViewComputedScale.covered * 4.1,
                    // child: futureImage(index),
                    child: Container(
                      color: Colors.lightGreen,
                      child: Image(
                        width:750,
                        image: CachedNetworkImageProvider(
                              'http://168.168.13.70:9500/dashboard/?action=accessFile&path=/.dj_data/temp/IMG_0578.HEIC-small.jpg'),
                      ),
                    ),
                  );
                },

the width:750 is don't work,it is show the img's original size
I mean.i want small image can be fill the parent box...just like PhotoViewGalleryPageOptions show