<div class="container">
  <div class="overlay">   
  </div>
</div>

.container {
  background-size: 1000px auto;
  width: 1000px;
  height: 550px;
  background-image: url("https://i.ibb.co/c3s1RYG/coratec.jpg");
  margin-left: auto;
  margin-right: auto;
}
.overlay {
  background: transparent linear-gradient(135deg,rgba(40, 146, 207, 0.85) 0%, rgba(134, 70, 252, 0.85) 100%) repeat scroll 0% 0%;
  height: 100%;
}