Включить все ресурсы в папку ресурсов, расположенную в каталоге приложения
мой файл pubspec выглядит как
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- assets/
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.io/assets-and-images/#resolution-aware.
использовать его как
Image.asset('assets/logo.png')
makeво избежание ошибок обязательно сделайте отступ.