PHP 프로젝트에서 이미지 처리 및 워터마크 추가를 구현하는 방법은 무엇입니까?

function resizeImage($srcFile, $dstFile, $newWidth, $newHeight) {
   list($srcWidth, $srcHeight, $srcType) = getimagesize($srcFile);
   $srcImage = imagecreatefromjpeg($srcFile);
   $dstImage = imagecreatetruecolor($newWidth, $newHeight);
   imagecopyresampled($dstImage, $srcImage, 0, 0, 0, 0, $newWidth, $newHeight, $srcWidth, $srcHeight);
   imagejpeg($dstImage, $dstFile);
   imagedestroy($srcImage);
   imagedestroy($dstImage);
}

function addWatermark($srcFile, $dstFile, $watermarkFile) {
   $srcImage = imagecreatefromjpeg($srcFile);
   $watermarkImage = imagecreatefrompng($watermarkFile);
   $srcWidth = imagesx($srcImage);
   $srcHeight = imagesy($srcImage);
   $watermarkWidth = imagesx($watermarkImage);
   $watermarkHeight = imagesy($watermarkImage);
   $posX = ($srcWidth - $watermarkWidth) / 2;
   $posY = ($srcHeight - $watermarkHeight) / 2;
   imagecopy($srcImage, $watermarkImage, $posX, $posY, 0, 0, $watermarkWidth, $watermarkHeight);
   imagejpeg($srcImage, $dstFile);
   imagedestroy($srcImage);
   imagedestroy($watermarkImage);
}