如何在magento中进行图像类型验证。

I am new to magento. I just want to do image validation in magento but i am struggling alot. I used ajax validation but append() function in jquery is not supporting in magento, So i dont know how to do this.

My ajax code:

           jQuery(function () { 
    var url =  jQuery('#image_url').val();
    var vendorImage = jQuery('#vendor_logo');
     vendorImage.on("change", function () {
        var fd = new FormData();
        var file = jQuery('#vendor_logo')[0].files[0];
        if (file) {   
            fd.append('vendor_logo', file);

        }
        jQuery.ajax({
            url: url,
            type: 'POST',
            cache: false,
            data: fd,
            success: function (result) { 
                alert(0);
                alert(result);
                jQuery("#output").html("Upload success.");
            }
        });

    });
});

I am getting error for append() function.

I think It would be better if i use add rule in validation.js file My code here:

        Validation.add('validate-imgtype', 'Please choos valid image', function(v) {
        var Image = jQuery(v).val();
        var extension = Image.split('.').pop().toUpperCase();
        if (extension!="PNG" && extension!="JPG" && extension!="GIF" && extension!="JPEG"){
            return extension;
        }
       });

But the above add rule code also not working.

Can anyone help me to resolve this???

Thanks in advance.

If you are asking for image validation in magento you can try doing

if($this->getRequest()->isPost())
  {
    if(isset($_FILES['myfileupload']['name']) and (file_exists($_FILES['myfileupload']['tmp_name'])))
    {
      $path = Mage::getBaseDir() . '/myfileupload';
      if(!file_exists($path))
      { mkdir($path, 777, true); }

      try {
      $myfileupload = $_FILES['myfileupload']['name'];
      $uploader = new Varien_File_Uploader('myfileupload');
      $uploader->setAllowedExtensions(array('png', 'gif', 'jpeg', 'jpg', 'pdf'));
      $uploader->setAllowCreateFolders(true);
      $uploader->setAllowRenameFiles(false);
      $uploader->setFilesDispersion(false);
      $uploader->save($path, $myfileupload);
      } catch (Exception $e) {
        echo 'Error';
      }
    }
  }