这样做可以将PNG安全地转换为白色透明的JPG。
$image = imagecreatefrompng($filePath);$bg = imagecreatetruecolor(imagesx($image), imagesy($image));imagefill($bg, 0, 0, imagecolorallocate($bg, 255, 255, 255));imagealphablending($bg, TRUE);imagecopy($bg, $image, 0, 0, 0, 0, imagesx($image), imagesy($image));imagedestroy($image);$quality = 50; // 0 = worst / smaller file, 100 = better / bigger file imagejpeg($bg, $filePath . ".jpg", $quality);imagedestroy($bg);



