Get rid of the leading / in your path to the png. It should be images/p8.png.
/
images/p8.png
Also, consider using the cleaner Image.asset constructor, for example:
Image.asset
new Image.asset('images/p8.png', width: 100.0, height: 100.0)
One thing to note is the 'assets:' tag must be correctly indented with the 'flutter:' tag, but it only throws an error occasionally when loading an asset. So this won't work:
flutter: assets: - images/
But this will:
Add '/' correctly in all image paths
In Android Studio,
Tools->Flutter->Flutter Clean