This is a mixture of FileImage and NetworkImage. It will download the image from the url once, save it locally in the file system, and then use it from there in the future.

In more detail:

Given a file and url of an image, it first tries to read it from the local file. It decodes the given File object as an image, associating it with the given scale.

However, if the image doesn't yet exist as a local file, it fetches the given URL from the network, associating it with the given scale, and then saves it to the local file. The image will be cached regardless of cache headers from the server.


  • If the provided url is null or empty, NetworkToFileImage will default to FileImage. It will read the image from the local file, and won't try to download it from the network.

  • If the provided file is null, NetworkToFileImage will default to NetworkImage. It will download the image from the network, and won't save it locally.


Import the package

First, add network_to_file_image as a dependency in your pubspec.yaml

Then, import it:

import 'package:network_to_file_image/network_to_file_image.dart';

Use the package

If you also listed path_provider in your pubspec.yaml file:

path_provider: ^0.4.1

Then you can create a file from a file name:

Future<File> file(String filename) async {
  Directory dir = await getApplicationDocumentsDirectory();
  String pathName = p.join(dir.path, filename);
  return File(pathName);

var myFile = await file("myFileName.png"),

Then, create the image:

Image(image: NetworkToFileImage(url: "", file: myFile))

If you make debug=true it prints to the console whether the image was read from the file or fetched from the network:

Image(image: NetworkToFileImage(url: "", file: myFile, debug: true))    

Don't forget to check the example tab.


You can set mock files. Please see methods setMockFile(File file, Uint8List bytes) and clearMockFiles().

See also




Built-in types and core primitives for a Flutter application. [...]


Support for asynchronous programming, with classes such as Future and Stream. [...]
Classes and utilities that supplement the collection support in dart:core. [...]
Encoders and decoders for converting between different data representations, including JSON and UTF-8. [...]
Built-in types, collections, and other core functionality for every Dart program. [...]
Interact with developer tools such as the debugger and inspector. [...]
Mathematical constants and functions, plus a random number generator. [...]
Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types. [...]


File, socket, HTTP, and other I/O support for non-web applications. [...]
Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages. [...]