first image database upload

                <?php if(!isset ($_POST['invia'])){ ?>
                <form id="firstimg" method="POST">
                <div class="module_content">
                    <fieldset>
                        <label>Seleziona articolo</label>
                        <select for="article">
                            <option value="" disabled="disabled" selected="selected">-</option>
                            <?php
                            $res=mysql_query("SELECT post_title FROM wp_posts WHERE post_status='publish' AND post_type='post' ORDER BY post_date DESC");
                            if($res && mysql_num_rows($res)>0){
                                while($row=mysql_fetch_assoc($res)){
                                    $titolo=$row['post_title'].""; ?>
                                    <option value="<?php echo $titolo; ?>"><?php echo $titolo; ?></option>
                            <?php }
                            } else { ?>
                                <option value="" disabled='disabled'>Errore Connessione</option>
                            <?php } ?>
                        </select>
                    </fieldset>
                    <fieldset>
                        <label>URL Immagine</label>
                        <input type="text" name="img" id="img">
                    </fieldset><div class="clear"></div>
                </div>
                <footer>
                    <div class="submit_link">
                        <input type="submit" name="invia" id="invia" value="Invia" class="alt_btn">
                    </div>
                </footer>
                </form>
                <?php
                } else { ?>
                <div class="module_content">
                <fieldset>
                <?php
                    $article = mysql_real_escape_string($_POST['article']);
                    $img = mysql_real_escape_string($_POST['img']);
                    if($article == "" || $img == ""){
                        echo "Devi riempire tutti i campi";
                    } else {
                        $inviaimg=mysql_query("INSERT INTO wp_posts (post_firstimg) VALUES ('$img') WHERE post_title='$article'");
                        if($inviaimg){
                            echo "Immagine caricata";
                        } else {
                            echo "Caricamento fallito";
                        }
                    } ?>
                    </fieldset>
                    </div>
            <?php } ?>