What is the difference between an "Image" and "ImageProvider" in Flutter?

Question

There are answers related to this topic but they offer workarounds rather than explanations.

Why can't an Image be used where an ImageProvider is required? Conceptually they sound the same to me.

child: new CircleAvatar(
  backgroundImage: NetworkImage("https..."),        // works
  backgroundImage: Image.asset('images/image.png'), // error
),

The error generated by trying to use an image directly is:

error: The argument type 'Image' can't be assigned to the parameter type 'ImageProvider'.

Please avoid using new keyword as per [effective dart guidelines](https://dart.dev/guides/language/effective-dart/usage#dont-use-new) — Ravinder Kumar, Nov 27 '19 at 18:29

score 34 · Answer 1 · answered Jan 18 '21 at 11:03

Image vs ImageProvider

An image provider is what provides the image to an Image widget. ;D

The image provider doesn't necessarily have the image right there but it knows how to get it.

Getting an Image

If you need an Image widget, then use one of these:

Image.asset()
Image.network()
Image.file()
Image.memory()

Getting an ImageProvider

If you need an ImageProvider, then use one of these:

AssetImage()
NetworkImage()
FileImage()
MemoryImage()

Converting an ImageProvider to an Image

If you have an ImageProvider object and you want an Image widget, then do the following:

Image(
  image: myImageProvider,
)

Converting an Image to an ImageProvider

If you have an Image widget and you need its ImageProvider, then do the following:

myImageWidget.image

score 6 · Accepted Answer · answered Nov 27 '19 at 19:06

6

An Image is a widget that displays an image.

The ImageProvider instead allows you to identify an image without knowing exactly where is the final asset. The place of the asset will be resolved later when someone wants to read the image.

answered Nov 27 '19 at 19:06

Ricardo Markiewicz

982
8
11

score 2 · Answer 3 · answered Jan 14 '22 at 13:56

Actually Every background and Foreground Decoration will accept only ImageProvider like AssetImage(),NetworkImage(),FileImage(),MemoryImage()...

And when you try to build a widget then its take Image.asset(),Image.network(), Image.file(), Image.memory()...

score 1 · Answer 4 · answered Jun 06 '23 at 14:15

In Flutter, ImageProvider is an abstract class that represents a way to obtain an image.

It serves as a bridge between the image data source and the Image widget that displays the image on the screen. The purpose of the ImageProvider is to decouple the image loading process from the widget tree.

The ImageProvider class has various subclasses that provide different ways to load images, such as:

AssetImage: Loads an image from the application's assets.

NetworkImage: Loads an image from a URL.

FileImage: Loads an image from a file on the device.

MemoryImage: Loads an image from raw bytes in memory.

ResizeImage: Modifies the size of an image loaded by another ImageProvider.

To use an ImageProvider, you typically pass it as an argument to the Image widget's image parameter. Here's an example of using AssetImage to load an image from the assets:

Example:

Image( image: AssetImage('assets/images/my_image.png'),);