Rounded Corners Image in Flutter

Use ClipRRect it will work perfectly

ClipRRect(
    borderRadius: BorderRadius.circular(8.0),
    child: Image.network(
        subject['images']['large'],
        height: 150.0,
        width: 100.0,
    ),
)

You can also use CircleAvatar, which comes with flutter

CircleAvatar(
  radius: 20,
  backgroundImage: NetworkImage('https://via.placeholder.com/140x100')
)

Using ClipRRect you need to hardcode BorderRadius, so if you need complete circular stuff, use ClipOval instead.

ClipOval(
  child: Image.network(
    "image_url",
    height: 100,
    width: 100,
    fit: BoxFit.cover,
  ),
),