这个代码使用 cURL来取得一张图片，然后在页面上展示它的缩略图。但不保存。

 <?php  //$url = "http://share.meebo.com/content/katy_perry/wallpapers/3.jpg";  $url = $_GET['url'];    $url = str_replace("http:/","http://",$url);    $allowed = array('jpg','gif','png');  $pos = strrpos($_GET['url'], ".");  $str = substr($_GET['url'],($pos + 1));    $ch = curl_init();  $timeout = 0;  curl_setopt ($ch, CURLOPT_URL, $url);  curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);    // Getting binary data  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);  curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);    $image = curl_exec($ch);  curl_close($ch);  // output to browser  $im = @imagecreatefromstring($image);    $tw = @imagesx($im);  if(!$tw){      // Font directory + font name      $font = '../../fonts/Austrise.ttf';      // Size of the font      $fontSize = 18;      // Height of the image      $height = 32;      // Width of the image      $width = 250;      // Text      $str = 'Couldn\'t get image.';      $img_handle = imagecreate ($width, $height) or die ("Cannot Create image");      // Set the Background Color RGB      $backColor = imagecolorallocate($img_handle, 255, 255, 255);      // Set the Text Color RGB      $txtColor = imagecolorallocate($img_handle, 20, 92, 137);       $textbox = imagettfbbox($fontSize, 0, $font, $str) or die('Error in imagettfbbox function');      $x = ($width - $textbox[4])/2;      $y = ($height - $textbox[5])/2;      imagettftext($img_handle, $fontSize, 0, $x, $y, $txtColor, $font , $str) or die('Error in imagettftext function');      header('Content-Type: image/jpeg');      imagejpeg($img_handle,NULL,100);      imagedestroy($img_handle);   }else{      if($str == 'jpg' || $str == 'jpeg')          header("Content-type: image/jpeg");      if($str == 'gif')          header("Content-type: image/gif");      if($str == 'png')          header("Content-type: image/png");      $th = imagesy($im);      $thumbWidth = 200;      if($tw <= $thumbWidth){          $thumbWidth = $tw;      }      $thumbHeight = $th * ($thumbWidth / $tw);      $thumbImg = imagecreatetruecolor($thumbWidth, $thumbHeight);      if($str == 'gif'){          $colorTransparent = imagecolortransparent($im);          imagefill($thumbImg, 0, 0, $colorTransparent);          imagecolortransparent($thumbImg, $colorTransparent);      }      if($str == 'png'){          imagealphablending($thumbImg, false);          imagesavealpha($thumbImg,true);          $transparent = imagecolorallocatealpha($thumbImg, 255, 255, 255, 127);          imagefilledrectangle($thumbImg, 0, 0, $thumbWidth, $thumbHeight, $transparent);      }      imagecopyresampled($thumbImg, $im, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $tw, $th);          if($str == 'jpg' || $str == 'jpeg'){          imagejpeg($thumbImg, NULL, 100);      }      if($str == 'gif'){          imagegif($thumbImg);      }      if($str == 'png'){          imagealphablending($thumbImg,TRUE);          imagepng($thumbImg, NULL, 9, PNG_ALL_FILTERS);      }                imagedestroy($thumbImg);  }  ?>