How can you check if the GD library is installed on a B-One.net server using PHP?

To check if the GD library is installed on a B-One.net server using PHP, you can use the `extension_loaded` function to check if the GD extension is loaded. If it is loaded, then the GD library is installed on the server. You can use this check to determine if you can use GD functions for image manipulation in your PHP code.

if (extension_loaded('gd')) {
    echo 'GD library is installed on this server.';
} else {
    echo 'GD library is not installed on this server.';
}