I have a specific sized canvas (let's say 400x300 pixels) and I have an image which could be any amount, I want to scale down (paying attention to ratios so it is proper ratio) and fit it inside the canvas, that part I know how to do. But I want to then make the canvas 400x300.
So an image let's say 300x600. It would be scaled to 150x300 (so it fits inside 400x300) and then centered and the image is "applied" to a white canvas of 400x300. And it would do that for any size image.
I don't know how to do the last part.