Image on non-root Canvas (behind UI Images)

I am trying to set a background image to a non-root Canvas in my scene. I am able to easily set the background image of the root Canvas and see it in the editor, but images set to any other Canvas do not show up. Even though I can add the Image component to it, I cannot see the image. I want to set a background image to the child Canvas since eventually it will contain other Image objects set in a grid layout, each with a transparent background. I’m new to this, so some help or guidance is very much appreciated.

you should set the root canvas in mode “Screen Space - Camera” and create a new camera for the root canvas

in this example the image with Hegel will be above the image with the texture of the wood.

I fixed this problem by placing the UI components in a Panel.