creating thumbnails form JPG (not GD)

[Anon]

I'm trying to create thumbnails from 1-4MB JPG files but I cannot install GD library 2.0.1 so I cannot use imagecreatetruecolor() function....
Here is my function.... HOW TO REWRITE IT so it does not have to use GD 2.0.1... to output JPG thumbnail images ....

function create_mini_jpg($file_big, $file_mini) {

$size = 210;

$srcjpeg = ImageCreateFromJPEG($file_big);


$srcwidth = ImageSX($srcjpeg);
$srcheight = ImageSY($srcjpeg);	

if ($srcwidth >= $srcheight) {		$factor = $srcwidth/$size;		
} else {				$factor = $srcheight/$size;		
}

$dstwidth = Round($srcwidth/$factor);
$dstheight = Round($srcheight/$factor);

$dstjpeg = ImageCreateTrueColor($dstwidth, $dstheight);
ImageCopyResampled($dstjpeg, $srcjpeg, 0, 0, 0, 0, $dstwidth, $dstheight, $srcwidth, $srcheight);

$quality=30;
ImageJpeg($dstjpeg, $file_mini, $quality);

ImageDestroy($srcjpeg);
ImageDestroy($dstjpeg); 

}