bad quality with imagecopyresampled [PHP4]

imagecopyresampled makes bad quality jpeg images when scaling them down, especially on areas of the same colour (i.e. large font). I am using antialiasing. I thought I'd try converting the images to png - imagecopyresampling them - and then save as jpeg, however I can't seem to get it to work! Here's some of the code I'm using: ///////////////////////////////////////////////////// imagecreatefromjpeg($src); // add convert here imagecopyresampled($destImage, $srcImage, 0, 0, 0, 0,$destSize[0],$destSize[1],$srcSize[0],$srcSize[1]); imagejpeg($destImage,$dest,$quality); ///////////////////////////////////////////////////// How can I convert the jpeg to png temporarily before imagecopyresample? Please help!