I need to display an image in the navigation bar like this:

but I can't because NavigationBarItem class needs an icon, so when I use ImageIcon widget I lose the colors. There are multiple colors in the image.
How to show the image in there or a way to make a colorful icon?
And when I use
BottomNavigationBarItem(
icon: ImageIcon(
NetworkImage('https://picsum.photos/250?image=9'),
),
title: Text('Image'),
),
