PHP上传图片

　　<form action="upload_file.php" method="post" enctype="multipart/form-data">
        <label for="file">filename:</label>
        <input type="file" name="file" id="file" />
        <br />
        <input type="submit" name="submit" value="submit" />
    </form>

<?php
if ((($_files["file"]["type"] == "image/gif")
|| ($_files["file"]["type"] == "image/jpeg")
|| ($_files["file"]["type"] == "image/pjpeg"))
&& ($_files["file"]["size"] < 2000000))
  {
  if ($_files["file"]["error"] > 0)
    {
    echo "return code: " . $_files["file"]["error"] . "<br />";
    }
  else
    {
    echo "upload: " . $_files["file"]["name"] . "<br />";
    echo "type: " . $_files["file"]["type"] . "<br />";
    echo "size: " . ($_files["file"]["size"] / 1024) . " kb<br />";
    echo "temp file: " . $_files["file"]["tmp_name"] . "<br />";

    if (file_exists("upload/" . $_files["file"]["name"]))
      {
      echo $_files["file"]["name"] . " already exists. ";
      }
    else
      {
      move_uploaded_file($_files["file"]["tmp_name"],
      "upload/" . $_files["file"]["name"]);
      echo "stored in: " . "upload/" . $_files["file"]["name"];
      }
    }
  }
else
  {
  echo "无效的文件";
  }