上传文件所以我应该怎么做标题？

We successfully set up image uploading on our server with nginx. Everything gets posted to /upload and then redirects to /file for processing. The file gets uploaded and stored, but there are headers at the top of the file.

------WebKitFormBoundaryqUwBABts5uiLHgDN

Content-Disposition: form-data; name="picture"; filename="coldplay.jpg"

Content-Type: image/jpeg

What am I to do with this? Do I strip these headers out with PHP and then save the file again?

Is uploading files with these headers expected behavior?

Here is the form:

<form action="/upload/"  id="upload3" method="post">
    <input type="file" id="file" name="picture" value=""/>
    <input type="submit" onclick="return uploadFiles(this.form);">
</form>

and js:

<script type="text/javascript">

    function uploadFiles(form) {
          var formData = new FormData(form);

          var url = "/upload/";
          var xhr = new XMLHttpRequest();
          xhr.open('POST', url, true);
          xhr.onload = function(e) {
            if (this.status == 200) {
              console.log(this.responseText);
            }
          };

          xhr.send(formData);  // multipart/form-data

          return false;
    }
</script>

I'm using these lines of code to strip the first four lines from our uploaded image files. I found it somewhere on SO and it works great -- unfortunately I don't know where it was.

$line_to_strip = 4;
$new_file = new SplFileObject($file_full_new, 'w');
foreach (new LimitIterator(new SplFileObject($file_full), $line_to_strip) as $line)
    $new_file->fwrite($line); 

I don't know if this is our permanent solution, however.