HTML Element Style How to - Set pictures in the div background


We would like to know how to set pictures in the div background.


<!DOCTYPE html>
<style type='text/css'>
#product1left {<!--from  ww  w . ja v  a2s.c  o  m-->
  width: 100px;
  height: 100px;
  background-color: red;
  background-size: 100%;
  <div id="product1left" class="product-cards-left"
    style="background-image: url('')">

The code above is rendered as follows: