AssetImage is not displaying image in flutter app

There may be two issues:

1.) Either you pubspec.yaml file is not having proper indention. Attaching snippet for reference.

flutter:  
  uses-material-design: true   
  assets:   
    - assets/

- assets/ will consider all the images in the directory.

2.) If you are using .jpg image then please change it to .jpeg wherever you are calling it.

Attaching the snippet for you reference

class _UserLoginState extends State<UserLogin> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          Image(image: AssetImage("assets/christmas.jpeg"),
          fit: BoxFit.cover,
        ],
      )
    );
  }
} 

i mentioned images files in wrong way. i put space between '-' and image name instead of tab.

assets:

- assets/images/logo.png

Don't put spaces between the character instead of tab in pubspec.yaml file

Make sure the folder you are referring in Image.asset contains the file.

For example:

Image.asset(
"./assets/images/loading.gif",
height: 125.0,
width: 125.0,
)

The folder should be:

C:\your_app_folder\assets\images

pubspec.yaml:

  assets:
    - assets/
    - assets/images/

Run flutter clean to clean the intermediate files and refresh.

Hot Reload was the issue in my case. I simply restarted the Android studio and re-run the app, it all worked!.