Insert Images at Database PHPMYSQL - php

Question

So im trying to upload/host images at my database but for some reason i cant archieve it.
Insert the Image:
<form method="post" action="actions/dados_insert.php" enctype="multipart/form-data">
<input type="file" name="imagem" />
</form>
dados_insert.php
<?php
if ( ! empty( $_POST ) ) {
$mysqli = new mysqli( 'localhost', 'root', '', 'valsil' );
$mysqli->set_charset("utf8");
if ( $mysqli->connect_error ) {
die( 'Connect Error: ' . $mysqli->connect_errno . ': ' . $mysqli->connect_error );
}
$sql = "INSERT INTO dados ( id_proposta, quantidade, posicao, unitario, titulo, `desc`, imagem ) VALUES ( '{$mysqli->real_escape_string($_POST['id_proposta'])}', '{$mysqli->real_escape_string($_POST['quantidade'])}', '{$mysqli->real_escape_string($_POST['posicao'])}', '{$mysqli->real_escape_string($_POST['unitario'])}', '{$mysqli->real_escape_string($_POST['titulo'])}', '{$mysqli->real_escape_string($_POST['desc'])}', '{$mysqli->real_escape_string($_FILES['imagem'])}' )";
$insert = $mysqli->query($sql);
if ( $insert ) {
header("Location: ". $_SERVER['HTTP_REFERER']);
exit();
} else {
die("Error: {$mysqli->errno} : {$mysqli->error}");
}
$mysqli->close();
}
?>
Update the Image:
<form method="post" action="actions/dados_update.php?id=<?php echo $row['id']; ?>" enctype="multipart/form-data">
<input type="file" name="imagem" />
</form>
dados_update.php
<?php
if ( ! empty( $_POST ) ) {
$mysqli = new mysqli( 'localhost', 'root', '', 'valsil' );
$mysqli->set_charset("utf8");
$id = $_GET['id'];
if ( $mysqli->connect_error ) {
die( 'Connect Error: ' . $mysqli->connect_errno . ': ' . $mysqli->connect_error );
}
$sql = "UPDATE dados SET quantidade = '{$mysqli->real_escape_string($_POST['quantidade'])}', posicao = '{$mysqli->real_escape_string($_POST['posicao'])}', unitario = '{$mysqli->real_escape_string($_POST['unitario'])}', titulo = '{$mysqli->real_escape_string($_POST['titulo'])}', `desc` = '{$mysqli->real_escape_string($_POST['desc'])}', imagem = '{$mysqli->real_escape_string($_FILES['imagem'])}' WHERE id =".$id;
$insert = $mysqli->query($sql);
if ( $insert ) {
header("Location: ". $_SERVER['HTTP_REFERER']);
exit();
} else {
die("Error: {$mysqli->errno} : {$mysqli->error}");
}
$mysqli->close();
}
?>
I would appreciate any help, theres something missing for sure, first time trying to upload images and already readed tutorials but still couldnt get the answer.
Cumps.