Check out example codes for "how to add images on images css". It will help you in understanding the concepts better.

Code Example 1

.element {
  background-image: url("imageFile.png");
}

Code Example 2

.parent {
  position: relative;
  top: 0;
  left: 0;
}
.image1 {
  position: relative;
  top: 0;
  left: 0;
  border: 1px red solid;
}
.image2 {
  position: absolute;
  top: 30px;
  left: 30px;
  border: 1px green solid;
}

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