Simple but complete code example to create and place an image into scene (no editor actions please!)

There are many explanations for adding images into a scene, but they vary a lot; some have too little info, and some include too much irrelevant stuff. I just need to get the bare-bones working, and I’ll take it from there.

I just need a simple (but complete! e.g., what to include at the top with “using”) example of the necessary code to create a canvas (assuming a canvas is necessary - is it?) and attaching an image that I have in my Assets folder. I assume it will be a GameObject that I can transform.

This needs to be all in code.