What are some common debugging techniques for resolving GdImage errors in PHP?

One common debugging technique for resolving GdImage errors in PHP is to check for errors returned by GdImage functions using `imagetypes()` or `imagecreatefromstring()` functions. Additionally, ensure that the image file exists and is accessible by the PHP script. Another technique is to increase the memory limit for image processing using `ini_set('memory_limit', '256M');` in your PHP script.

// Check if GD extension is loaded
if (!extension_loaded('gd')) {
    die('GD extension is not loaded');
}

// Check if image file exists and is accessible
$imagePath = 'path/to/image.jpg';
if (!file_exists($imagePath) || !is_readable($imagePath)) {
    die('Image file does not exist or is not readable');
}

// Increase memory limit for image processing
ini_set('memory_limit', '256M');