upload.dart

 Widget build(BuildContext context) {

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

      setState(() {
        _image = image;
          print('Image Path $_image');
      });
    
    }

    Future uploadPic(BuildContext context) async{
      
      String fileName = basename(_image.path);
       StorageReference firebaseStorageRef = FirebaseStorage.instance.ref().child(fileName);
       StorageUploadTask uploadTask = firebaseStorageRef.putFile(_image);
       StorageTaskSnapshot taskSnapshot=await uploadTask.onComplete;
       setState(() {
          print("Profile Picture uploaded");
          Scaffold.of(context).showSnackBar(SnackBar(content: Text('Profile Picture Uploaded')));
       });
    
    }

Can you please share the basename function. Thank you.

I had the same issue, they failed to tell you to use the following import package:
import 'package:path/path.dart';