title: Image resize issue in PHP - gd creates ugly resized images
body: <p>I am creating thumbnails of fixed height and width from my PHP script using the following function</p>
  
  <pre><code>/*creates thumbnail of required dimensions*/
  function createThumbnailofSize($sourcefilepath,$destdir,$reqwidth,$reqheight,$aspectratio=false)
  {
      /*
       * $sourcefilepath =  absolute source file path of jpeg
       * $destdir =  absolute path of destination directory of thumbnail ending with "/"
       */
      $thumbWidth = $reqwidth; /*pixels*/
      $filename = split("[/\\]",$sourcefilepath);
      $filename = $filename[count($filename)-1];
      $thumbnail_path = $destdir.$filename;
      $image_file = $sourcefilepath;
  
      $img = imagecreatefromjpeg($image_file);
      $width = imagesx( $img );
      $height = imagesy( $img );
  
      // calculate thumbnail size
      $new_width = $thumbWidth;
      if($aspectratio==true)
      {
          $new_height = floor( $height * ( $thumbWidth / $width ) );
      }
      else
      {
          $new_height = $reqheight;
      }
  
      // create a new temporary image
      $tmp_img = imagecreatetruecolor( $new_width, $new_height );
  
      // copy and resize old image into new image
      imagecopyresized( $tmp_img, $img, 0, 0, 0, 0, $new_width, $new_height, $width, $height );
  
      // save thumbnail into a file
  
      $returnvalue = imagejpeg($tmp_img,$thumbnail_path);
      imagedestroy($img);
      return $returnvalue;
  }
  </code></pre>
  
  <p>and I call this function with following parameters</p>
  
  <pre><code>createThumbnailofSize($sourcefilepath,$destdir,48,48,false);
  </code></pre>
  
  <p>but the problem is the resulting image is of very poor quality, when I perform the same operation with Adobe Photo shop, it performs a good conversion.. why it is so? I am unable to find any quality parameter, through which I change the quality of output image..</p>