php $ _files一直在上传

I have a script that performs some simple editing which works fine, the problem is even once the image is uploaded successfully and I refresh the page the same image is being created even though it's not selected from the file input on form submission:

<form  method="post"  enctype="multipart/form-data" id="<?php echo $_SERVER['PHP_SELF']; ?>">
                     <fieldset id="product-images">
                    <input type="file" id="image" name="image" />
                    <input type="submit" name="picture" value="upload Picture"/>
</form>

Here's the php

 <?php if(isset($_POST['picture']) && !empty($_FILES)){(uploadImage($_FILES['image'])} ;?>   

function uploadImage($image)
{
    $id = intval($_GET['id']);
    $size = 75; // the thumbnail height

    $filedir = '../img/products/'; // the directory for the original image
    $thumbdir = '../img/products/thumbs/'; // the directory for the thumbnail image
    $prefix = 'small_'; // the prefix to be added to the original name

    $maxfile = '2000000';
    $mode = '0666';

    $userfile_name = $image['name'];
    $userfile_tmp = $image['tmp_name'];
    $userfile_size = $image['size'];
    $userfile_type = $image['type'];

    if (isset($image['name'])) 
    {
        $prod_img = $filedir.$userfile_name;
        $url = strstr($userfile_name, '.', true);
        $type = strstr($userfile_name, '.');


        $prod_img_thumb = $thumbdir.$prefix.$userfile_name;
        move_uploaded_file($userfile_tmp, $prod_img);
        chmod ($prod_img, octdec($mode));

        $sizes = getimagesize($prod_img);
        $width = $size[0];
        $height = $size[1];
        if($width > $height) $biggestSide = $width;
        else $biggestSide = $height;

        //The crop size will be half that of the largest side
        $cropPercent = 1;
        $cropWidth   = $biggestSide*$cropPercent;
        $cropHeight  = $biggestSide*$cropPercent;

        //getting the top left coordinate
        $c1 = array("x"=>($width-$cropWidth)/2, "y"=>($height-$cropHeight)/2);

        $aspect_ratio = $sizes[1]/$sizes[0]; 

        if ($sizes[1] <= $size)
        {
            $new_width = $sizes[0];
            $new_height = $sizes[1];
        }else{
            $new_height = $size;
            $new_width = abs($new_height/$aspect_ratio);
        }

        $destimg=ImageCreateTrueColor($new_width,$new_height)
            or die('Problem In Creating image');
        $srcimg=ImageCreateFromJPEG($prod_img)
            or die('Problem In opening Source Image');
        if(function_exists('imagecopyresampled'))
        {
            imagecopyresampled($destimg,$srcimg,0,0,$c1['x'],$c1['y'],$new_width,$new_height,ImageSX($srcimg),ImageSY($srcimg))
            or die('Problem In resizing');
        }else{
            Imagecopyresized($destimg,$srcimg,0,0,0,0,$new_width,$new_height,ImageSX($srcimg),ImageSY($srcimg))
            or die('Problem In resizing');
        }
        ImageJPEG($destimg,$prod_img_thumb,90)
            or die('Problem In saving');
        imagedestroy($destimg);
        imagedestroy($srcimg);

        insertURL($id, $url, $type);

    }


}

Which page are you refreshing? the "your uploaded completed" one? That stands to reason - it's the result page of the upload. Refreshing that one would give you the usual "this page is the result of a POST? redo the POST?" type warning, which would re-submit the entire form, including the file.

To prevent a refresh from re-doing the upload, you have to redirect the user elsewhere after the form handling code's finished.

<?php

if ($_SERVER['REQUEST_METHOD'] == 'POST') {

    // handle the upload

    if (/*form processed OK*/) {
       header("Location: successpage.php");
       exit();
    } else {
       // report any error conditions
    }
}

// show the form

?>

Read about POST-REDIRECT-GET here:

http://en.wikipedia.org/wiki/Post/Redirect/Get

When you refresh the page the form is resend, and everything happens again. A general rule when working with forms is to redirect the user to another page after your script has processed the submitted form. Then, even if they reload the page, they will not resubmit anything and problems like this will be avoided