<!DOCTYPE html>
<html>
<head>
<style>
.container {
position: relative;
width: 50%;
}
.image {
display: block;
width: 100%;
height: auto;
}
.overlay {
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
height: 100%;
width: 100%;
opacity: 0;
transition: .7s ease;
background-color: #339c57;
}
.container:hover .overlay {
opacity: 1;
}
.text {
color: white;
font-size: 18px;
position: absolute;
top: 50%;
left: 50%;
-webkit-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);