Setting the filter property to brightness(100%) changes how bright an image is, where 100% is the image's default level.
<head>
<link rel="stylesheet" href="style.css">
</head>
<body>
<h3>John's Smart Lights</h3>
<img src="https://mimo.app/i/light-bulb.png">
</body>
img {
filter: brightness(100%);
width: 150px;
}
The lower the brightness, the darker the image. We can see it in action with brightness set to 20%.
<head>
<link rel="stylesheet" href="style.css">
</head>
<body>
<h3>John's Smart Lights</h3>
<img src="https://mimo.app/i/light-bulb.png">
</body>
img {
filter: brightness(20%);
width: 150px;
}