mysqli存储php变量不值

This is driving me nuts. I am using the jQuery image upload and crop from http://www.webmotionuk.co.uk/php-jquery-image-upload-and-crop/

I am using a modified version of the suggestion on here to store the file location in a MySQL database. The mod is that I use INSERT on a table it works great except one thing, the 'owner' variable $id is being stored as $id and not as the value of $id. I can echo the value if $id on each $_POST so I know it's there.

I am pretty sure my syntax is correct but I don't understand why it is doing this.

    $cropped = resizeThumbnailImage($thumb_image_location, $large_image_location,$w,$h,$x1,$y1,$scale);
    //connect to the database
    include 'config.php';
    // check connection
    if (mysqli_connect_errno()) {
        exit('Connect failed: '. mysqli_connect_error());
    } 
    $sql = "INSERT INTO `photos` (`id`,`owner`,`url`) VALUES ('id','".$id."','".$thumb_image_location."')";
    // Performs the $sql query on the server to insert the values
    if ($conn->query($sql) === TRUE) {
        $conn->close();}
//Reload the page again to view the thumbnail
header("location:".$_SERVER["PHP_SELF"]);
exit();

The first line is 246 and the last 3 are the orginal 247-250.

Thanks for any help you can provide.

Ok, I don't know if this is my brain fart or an issue with PHP or a bit of both. I have $id assigned from the _SESSION variable in the header of each page AND (having forgotten that) I was passing $id as _POST data (same value). Once I cut out the _POST data passing and just pulled the _SESSION variable it works fine. But assigning a variable multiple times shouldn't be an issue, should it?

the query line needs to be like this:

$sql = "INSERT INTO `photos` (`id`,`owner`,`url`) VALUES ('id','$id','$thumb_image_location')";

your syntax works fine too, as seen here

this is how my syntax works, here

Note: both work the same, so still trying to figure out what's wrong in OP's code.