สอบถามเกี่ยวกับการ ดักชนิดไฟล์และขนาดไฟล์ได้อย่างไร.....

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
<?php
include("../../../includes/config.inc.php");
 $id = $_POST['v_id'];
 $sql = "SELECT * FROM school_gallery_category where gallery_category_id = '$id'";
 $query = mysql_query($sql)or die("Error Query [".$sql."]");
 $row = mysql_fetch_array($query);
 $dir_img = $row['gallery_category_id'];
 $dir_thumb= $row['gallery_category_id']."/thumb";
 if(!file_exists($dir_img)&&!file_exists($dir_thumb)){
 	mkdir($dir_img);
	mkdir($dir_thumb);
 }
		for($i=0;$i<count($_FILES["upfile"]);$i++){
			if($_FILES["upfile"]["name"][$i] != ""){	
				$path = $dir_img."/".$_FILES["upfile"]["name"][$i];
					if(move_uploaded_file($_FILES["upfile"]["tmp_name"][$i],$path)){
      			  $gallery_filename = $_FILES["upfile"]["name"] [$i];
				  $gallery_thumb = "thumb_".$_FILES["upfile"]["name"] [$i];
				  $gallery_caption = trim($_REQUEST['caption'][$i]) ;
  			     //echo $gallery_caption;
		$sql = "INSERT  into  school_gallery  (gallery_image_id,gallery_filename,gallery_thumbname,gallery_caption,gallery_category_id ) values ('' , '$gallery_filename' , '$gallery_thumb','$gallery_caption','$id' ) ";
			mysql_query($sql);		
			
				$thumb_path = $dir_thumb."/thumb_".$_FILES["upfile"]["name"][$i];
				list($w1, $h1) = getimagesize($path);		// Get new dimensions 
				$quality = 100;
				$w2 = 100 ; # 
				$percent = $w2 / $w1 ;
				$h2 = $h1 * $percent ;
				$h2 = 80 ; # 
				$percent = $h2 / $h1 ;
				$w2 = $w1 * $percent ;
				$w2 = 120 ; # 
				$h2 = 90 ; # 
				$im = imagecreatetruecolor($w2+4, $h2+4);	
				$im1 = imagecreatefromjpeg($path);
				$dark = imagecolorallocate($im,185,185,185);	// dark
				$light = imagecolorallocate($im,230,230,230);	
				$white = imagecolorallocate($im,254,254,254);
				imagefilledrectangle($im, 0, 0, $w2+3 , $h2+3, $white);	
				imagefilledrectangle($im, 4, 4, $w2+4 , $h2+4, $light);
				imagefilledrectangle($im, 3, 3, $w2+2 , $h2+2, $dark);
				imagecopyresampled($im, $im1, 0, 0, 0, 0, $w2, $h2, $w1, $h1);
				imagestring($im, 5, 5, $h2 - 20, "", $light);
				imagejpeg($im, $thumb_path , $quality);	# %
				imagedestroy($im);
				imagedestroy($im1);
		}
	}
}	
echo "<script>window.location='galleryform.php'</script>" ;
?>