What function in PHP can be used to extract the dimensions of an image file?

To extract the dimensions of an image file in PHP, you can use the `getimagesize()` function. This function returns an array containing the width and height of the image, as well as other information like image type and attributes. By using `getimagesize()`, you can easily retrieve the dimensions of an image file and use them in your PHP code.

$imageFile = 'image.jpg';
$imageSize = getimagesize($imageFile);

$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];

echo "Image width: $imageWidth, Image height: $imageHeight";