Flutter circle file image with clip oval

You can use CircleAvatar widget to display the obtained image to make it circular.

import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

void main() => runApp(new MaterialApp(debugShowCheckedModeBanner: false, home: new MyApp()));

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {
  File _image;

  Future getImage() async {
    var image = await ImagePicker.pickImage(source: ImageSource.camera);

    setState(() {
      _image = image;
    });
  }
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Home'),
      ),
      body: new Center(
        child: _image == null
            ? new Text('No image selected.')
            : new CircleAvatar(backgroundImage: new FileImage(_image), radius: 200.0,),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: getImage,
        tooltip: 'Pick Image',
        child: new Icon(Icons.add_a_photo),
      ),
    );
  }
}

You can also use ClipOval to circle the image. Just wrap your file image with ClipOval.

ClipOval(
  child: FileImage(_image)
),