How to wisely choose image resolution based on its container size?

Given:

1. I have a container of 64px * 64px which is used to display an image
2. I have an image of a very high resolution (5000px * 5000px)

What resolution would be optimal for the image?

Assuming that website will not be zoomed and I want image to look perfect on all possible devices.

P.S. My assumption is that 64px * 64px is not a suitable resolution for image because there are devices with pixel ratio > 1.