What is the difference between using imagesx with a resource versus a GdImage instance?

When working with images in PHP using the GD library, the difference between using imagesx with a resource versus a GdImage instance is that imagesx is used with a resource (such as the result of imagecreatefromjpeg) to get the width of the image, while a GdImage instance is an object-oriented representation of an image created with the imagecreatefromjpeg function. When using a GdImage instance, you can access properties and methods specific to that object, such as getWidth().

// Using imagesx with a resource
$imageResource = imagecreatefromjpeg('image.jpg');
$imageWidth = imagesx($imageResource);
echo 'Image width: ' . $imageWidth;

// Using a GdImage instance
$imageInstance = new GdImage('image.jpg');
$imageWidth = $imageInstance->getWidth();
echo 'Image width: ' . $imageWidth;