phpでgdライブラリを使って、ウェブページの中のすべての写真をダウンロードすることを実現します。

<?php
header("Content-type:text/html ; charset=utf-8");
if (!empty($_POST['submit'])){
 $url = $_POST['url'];
 //                
 $url_fields = parse_url($url);
 $main_url = $url_fields['host'];
 $base_url = substr($url,0,strrpos($url, '/')+1);
 //      
 //       
 $opts = array('http'=>array('request_fulluri'=>true));
 $context = stream_context_create($opts);
 $content = file_get_contents($url,false,$context);
 //  img  ,             $matches
 $reg = "/<img.*?src=\"(.*?)\".*?>/i";
 preg_match_all($reg, $content, $matches);
 $count = count($matches[0]);
 for ($i=0; $i<$count; $i++){
 /*      url     
  *$matches[1][$i] = strtolower($matches[1][$i]);
 */
 //                
 if (!strpos('a'.$matches[1][$i], 'http')){
  //  '/'  0   
  if (strpos('a'.$matches[1][$i], '/')){
  $matches[1][$i] = 'http://'.$main_url.$matches[1][$i];
  }else{
  $matches[1][$i] = $base_url.$matches[1][$i];
  }
 }
 }
 //       
 $img_arr = array_unique($matches[1]);
 //        
 $getImg = new DownImage();
 $url_count = count($img_arr);
 for ($i=0; $i<$url_count; $i++){
 $getImg->source = $img_arr[$i];
 $getImg->save_address = './pic/';
 $file = $getImg->download();
 }
 echo "    ！  ，   ！";
}
class DownImage{
 public $source;//    URL
 public $save_address;//      
 public $set_extension; //       
 public $quality; //     （0~100,100  ，  75  ）
 //    （  GD     ）
 public function download(){
 //        
 $info = @getimagesize($this->source);
 //       
 $mime = $info['mime'];
 $type = substr(strrchr($mime, '/'), 1);
 //                     
 switch($type){
  case 'jpeg':
  $img_create_func = 'imagecreatefromjpeg';
  $img_save_func = 'imagejpeg';
  $new_img_ext = 'jpg';
  $image_quality = isset($this->quality) ? $this->quality : 100;
  break;
  case 'png':
  $img_create_func = 'imagecreatefrompng';
  $img_save_func = 'imagepng';
  $new_img_ext = 'png';
  break;
  case 'bmp':
  $img_create_func = 'imagecreatefrombmp';
  $img_save_func = 'imagebmp';
  $new_img_ext = 'bmp';
  break;
  case 'gif':
  $img_create_func = 'imagecreatefromgif';
  $img_save_func = 'imagegif';
  $new_img_ext = 'gif';
  break;
  case 'vnd.wap.wbmp':
  $img_create_func = 'imagecreatefromwbmp';
  $img_save_func = 'imagewbmp';
  $new_img_ext = 'bmp';
  break;
  case 'xbm':
  $img_create_func = 'imagecreatefromxbm';
  $img_save_func = 'imagexbm';
  $new_img_ext = 'xbm';
  break;
  default:
  $img_create_func = 'imagecreatefromjpeg';
  $img_save_func = 'imagejpeg';
  $new_img_ext = 'jpg';
 }
 //                 
 if (isset($this->set_extension)){
  $ext = strrchr($this->source,".");
  $strlen = strlen($ext);
  $newname = basename(substr($this->source,0,-$strlen)).'.'.$new_img_ext;
 }else{
  $newname = basename($this->source);
 }
 
 //        
 $save_address = $this->save_address.$newname;
 $img = @$img_create_func($this->source);
 if (isset($image_quality)){
  $save_img = @$img_save_func($img,$save_address,$image_quality);
 }else{
  $save_img = @$img_save_func($img,$save_address);
 }
 return $save_img; 
 }
}
?>
<form method="POST" action="">
  url  ：<input type="text" name="url" size=30 />
<input type="submit" name="submit" value="         " />
</form>