<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
img {
-moz-opacity: 0.5;
-khtml-opacity: 0.5;
opacity: 0.5;
}
img:hover {
-moz-opacity: 1;
-khtml-opacity: 1;
opacity: 1;
}
</style>
</head>
<body>
<h2>Hover over the image to see the effect</h2>
<img src="/uploads/media/default/0001/01/4982c4f43023330a662b9baed5a407e391ae6161.jpeg" alt="House" width="300">
</body>
</html>