Check out example codes for "crop image with circle css". It will help you in understanding the concepts better.

Code Example 1

background-image: url("url");
width:100px;
height:100px;
background-size:contain;
background-position:center;
border-radius:50%;

Code Example 2

.image-cropper {
  width: 100px;
  height: 100px;
  position: relative;
  overflow: hidden;
  border-radius: 50%;
}

img {
  display: inline;
  margin: 0 auto;
  height: 100%;
  width: auto;
}

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