What are the common pitfalls that PHP developers should be aware of when working with image manipulation functions in PHP, such as imagecopyresized?

One common pitfall when working with image manipulation functions like imagecopyresized in PHP is not properly handling errors or checking for valid image resources before performing operations. To avoid this issue, always check if the image resources are valid before manipulating them to prevent potential errors or crashes.

// Check if the image resources are valid before performing image manipulation
if ($srcImg !== false && $destImg !== false) {
    // Perform image manipulation operations here
    imagecopyresized($destImg, $srcImg, $destX, $destY, $srcX, $srcY, $destWidth, $destHeight, $srcWidth, $srcHeight);
} else {
    // Handle the case where the image resources are invalid
    echo "Invalid image resources";
}