I'm looking to create a script which when run will go through a directory and resize every image in the directory, and put the resized image in a thumbs dir.

Heres the thing though, I don't want the image to lose any quality because this is for my photography, not just a products page. I also dont want the image to be scaled down to a specific size, I want its dimentions to be a percentage of it's orriginal size to accomodate photos that were taken long ways..

Does anyone know how i would achieve this?

By the way, I have the looping throough the files bit sorted out, I just need to know of a function oor code snippet that will resize an image and not lose any quality.

thanks.

Here's a function I've used with pretty good results. Resizes jpg's really nicely.
I think I got it from PHP.net's docs...

/*
 Function createthumb($name,$filename,$new_w,$new_h)
 creates a resized image
 variables:
 $name  Original filename
 $filename Filename of the resized image
 $new_w  width of resized image
 $new_h  height of resized image
*/ 
function createthumb($name,$filename,$new_w,$new_h){
 //global $gd2;
 $system=explode(".",$name);
 if (preg_match("/jpg|jpeg/",$system[1])){$src_img=imagecreatefromjpeg($name);}
 if (preg_match("/png/",$system[1])){$src_img=imagecreatefrompng($name);}
 $old_x=imageSX($src_img);
 $old_y=imageSY($src_img);
 if ($old_x > $old_y) {
  $thumb_w=$new_w;
  $thumb_h=$old_y*($new_h/$old_x);
 }
 if ($old_x < $old_y) {
  $thumb_w=$old_x*($new_w/$old_y);
  $thumb_h=$new_h;
 }
 if ($old_x == $old_y) {
  $thumb_w=$new_w;
  $thumb_h=$new_h;
 }
 //if ($gd2==""){
   //$dst_img=ImageCreate($thumb_w,$thumb_h);
   //imagecopyresized($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y); 
 //}else{
  $dst_img=ImageCreateTrueColor($new_w,$new_h);//create canvas picture  
  $thumbBgColor = imagecolorallocate($dst_img, 255, 255, 255);
  imagefilledrectangle($dst_img, 0, 0, $new_w, $new_w, $thumbBgColor);
  $xoffset = 0;
  $yoffset = 0;
  //calculate image offset to center the thumbnail
  if ($new_w > $thumb_w){
   $xoffset = (int) (($new_w - $thumb_w) / 2);
  } 
  if ($new_h > $thumb_h){
   $yoffset = (int) (($new_h - $thumb_h) / 2);
  }
  imagecopyresampled($dst_img,$src_img,$xoffset,$yoffset,0,0,$thumb_w,$thumb_h,$old_x,$old_y); 
 //}
 if (preg_match("/png/",$system[1])){
  imagepng($dst_img,$filename); 
 } else {
  imagejpeg($dst_img,$filename); 
 }
 imagedestroy($dst_img); 
 imagedestroy($src_img); 
}

You can see how the thumbs look at this site's product pages - Well Beings. There's a link from the thumbnails to popup a window with the original sized image.

-Jeffery

If you have ImageMagik on your server you can do it much more efficiantly using convert.

list($width, $height, $type, $attr) = getimagesize($name);
	$height > $width ?
	exec("/usr/bin/convert -size 150x200  {$name}  -thumbnail 75x100 {$filename}")
	:
	exec("/usr/bin/convert -size 220x80  {$name}  -thumbnail 110x40 {$filename}");

I only add this because PHP-GD winges like hell in winter when your dealing with large images. ImageMagik dont care it just does.

I dont know if its available for Windows machines but its certainly packaged with every linux distro.

Ibbo

cheers guys, i'll give them a go tonight.