How to make centre cropped image responsive?

Question

Based on an existing answer, I have managed to centre crop an image. I am having trouble making the centre cropped image responsive, though.

Question

Answer 1

just give width in % instead of px .

.center-cropped-img {
    width: 640px;// add in %
    height: auto;
    overflow: hidden;
    margin: 10px auto;
    border: 1px red solid;
    position: relative;
}