<div class="container">
  <img src="img_avatar.png" alt="Avatar" class="image">
  <div class="overlay">
    <div class="text">Hello World</div>
  </div>
</div>

/* Container needed to position the overlay. Adjust the width as needed */
.container {
  position: relative;
  width: 50%;
}

/* Make the image to responsive */
.image {
  width: 100%;
  height: auto;
}

/* The overlay effect (full height and width) - lays on top of the container and over the image */
.overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: #008CBA;
  overflow: hidden;
  width: 100%;
  height: 100%;
  transform: scale(0);
  transition: .3s ease;
}

/* When you mouse over the container, the overlay text will "zoom" in display */
.container:hover .overlay {
  transform: scale(1);
}

/* Some text inside the overlay, which is positioned in the middle vertically and horizontally */
.text {
  color: white;
  font-size: 20px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}