Read carefilly your code
$reqModImages = $bdd->prepare('UPDATE images
SET
nm_img = :Nom_image,
info_img = :Infos_image,
prix_art = :Prix,
src_img = :URL_image,
type_img = :Type_image
WHERE id_img = :ID');
$reqModImages->execute(array(
'Nom_image' => strip_tags($_POST['NewName']),
'Infos_image' => Strip_tags($_POST['NewDetailsImages']),
'Prix' => strip_tags($_POST['NewCost']),
'Url_image' => $URL,
'Type_image' => $TypeFichier,
'ID' => strip_tags($_POST['id']),
));
Parameter names are case sensitives.