PHP Simple Image resize & thumbnail generator

Here’s an old image resize script, welcome to grab parts out of it and use as your own. Will need to hack it a bit to get it to work.

<?php
$property_id = 1; // for our little example here
define( "_IMAGE_PATH", "property_images/" );
// max dimensions allowed:
define( "_IMAGE_WIDTH", "640" );
define( "_IMAGE_HEIGHT", "480" );
define( "_IMAGE_THUMB_WIDTH", "100" );
define( "_IMAGE_THUMB_HEIGHT", "75" );
// grab the path to the temporary file (image) that the user uploaded
$photo = $_FILES['new_image']['tmp_name'];
// check if it exists
if ( is_uploaded_file( $photo ) ) {
 //the real image file name
 $real_name = strtolower( $_FILES['new_image']['name'] );
 // image type based on image file name extension:
 if ( strstr( $real_name, ".png" ) ) {
  $image_type = "png";
 } else if ( strstr( $real_name, ".jpg" ) ) {
  $image_type = "jpg";
 } else if ( strstr( $real_name, ".gif" ) ) {
  $image_type = "gif";
 } else {
  die( "Unsupported image type" );
 }
 // find the next image name we are going to save
 $x = 1;
 while ( true ) {
  $image_name = _IMAGE_PATH . "${property_id}/${x}.jpg";
  if ( ! is_file( $image_name ) ) {
   break;
  }
  $x ++;
 }
 // start processing the main bigger image:
 $max_width  = _IMAGE_WIDTH;
 $max_height = _IMAGE_HEIGHT;
 $size       = getimagesize( $photo );
 $width      = $size[0];
 $height     = $size[1];
 $x_ratio    = $max_width / $width;
 $y_ratio    = $max_height / $height;
 if ( ( $width <= $max_width ) && ( $height <= $max_height ) ) {
  $tn_width  = $width;
  $tn_height = $height;
 } else {
  if ( ( $x_ratio * $height ) < $max_height ) {
   $tn_height = ceil( $x_ratio * $height );
   $tn_width  = $max_width;
  } else {
   $tn_width  = ceil( $y_ratio * $width );
   $tn_height = $max_height;
  }
 }
 switch ( $image_type ) {
  case "png":
   $src = imagecreatefrompng( $photo );
   break;
  case "jpg":
   $src = imagecreatefromjpeg( $photo );
   break;
  case "gif":
   $src = imagecreatefromgif( $photo );
   break;
 }
 // destination resized image:
 $dst = imagecreatetruecolor( $tn_width, $tn_height );
 // resize original image onto $dst
 imagecopyresampled( $dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height );
 // write the final jpeg image..
 imagejpeg( $dst, $image_name, 100 ) or die( "Error: your photo
has not been saved. Please contact the administrator" );
 // time to clean up
 imagedestroy( $src );
 imagedestroy( $dst );

 // and now we do it alll again for the thumbnail:
 $max_width  = _IMAGE_THUMB_WIDTH;
 $max_height = _IMAGE_THUMB_HEIGHT;
 $size       = GetImageSize( $photo );
 $width      = $size[0];
 $height     = $size[1];
 $x_ratio    = $max_width / $width;
 $y_ratio    = $max_height / $height;
 if ( ( $width <= $max_width ) && ( $height <= $max_height ) ) {
  $tn_width  = $width;
  $tn_height = $height;
 } else {
  if ( ( $x_ratio * $height ) < $max_height ) {
   $tn_height = ceil( $x_ratio * $height );
   $tn_width  = $max_width;
  } else {
   $tn_width  = ceil( $y_ratio * $width );
   $tn_height = $max_height;
  }
 }
 switch ( $image_type ) {
  case "png":
   $src = imagecreatefrompng( $photo );
   break;
  case "jpg":
   $src = imagecreatefromjpeg( $photo );
   break;
  case "gif":
   $src = imagecreatefromgif( $photo );
   break;
 }
 $dst = imagecreatetruecolor( $tn_width, $tn_height );
 imagecopyresampled( $dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height );
 $thumbfile = $image_name . ".thumb.jpg";
 if ( file_exists( $thumbfile ) ) {
  unlink( $thumbfile );
 }
 imagejpeg( $dst, $thumbfile, 100 ) or die( "Error: your photo thumb has not been saved. Please contact the administrator" );
 imagedestroy( $src );
 imagedestroy( $dst );
}