PHP: Properly storing image names in MySQL DB - php

Question

I am storing images name inside on MySQL database. Everytime I perform an upload, I have it return a link back with the image name attached which then I extract the image name and saved to the database. I have corrections to some critical flaws but I am still facing issues of having blank spaces/ duplicate names inserted into my database even though I have established checkpoints.
How can I avoid duplication/blank spaces of file names?
Is there a better approach in storing names in DB?
Location of image inside webserver:
http://www.example.com/imageupload/uploads/medium/50038dc14afb7.jpg
Link in the browser:
http://www.example.org/imageupload/index.php?i=50038dc14afb7.jpg
PHP
<?
$images = retrieve_images();
insert_images_into_database($images);
function retrieve_images()
{
$images = explode(',', $_POST['i']);
return $images;
}
function insert_images_into_database($images)
{
if(!$images) //There were no images to return
return false;
$db = dbConn::getConnection();
foreach($images as $image)
{
$sql = "INSERT INTO `urlImage` (`image_name`) VALUES ( ? )";
$prepared = $db->prepare($sql);
$prepared->execute(array($image));
}
}
?>

Answer 1

First, the blank name issue can perharps be fixed by checking $_POST['i']:
if (!isset($_POST['i'])) {
echo "No image to upload!";
die();
}
Have you tried redirecting after uploading the image?
// When image is uploaded
header("Location: http://example.org/imageupload/index.php");
die();

Answer 2

you can change the image name at the time of upload,
rand() is the function, which return random value, so you can avoid the duplicate image name,
the date time option will return always new date time, so you can diffidently get unique image name
Ex.$imageName.rand().$extention;
OR
Ex. $date = new DateTime(now);
$date = $date->format('Y_m_d_H_i_s');
$imageName.$date.$extention;

Answer 3

a couple of things:
To make sure you have unique file names, use tempnam() (
http://php.net/manual/en/function.tempnam.php )
To avoid page reload issue, post the upload form to a different page, which redirects to a
different page (or the previous form page) after it finishes doing the upload.
This is unrelated to your question but your SQL prepared statement should be outside of the loop.