我想显示随机图像在不同的页面，没有重复从数据库在php

<?php
session_start();

// 假设你的数据库表名为 images，包含 id 和 path 字段
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 获取所有图像ID
$sql = "SELECT id FROM images";
$result = $conn->query($sql);

$allImages = [];
while ($row = $result->fetch_assoc()) {
    $allImages[] = $row['id'];
}

// 移除已经显示过的图像ID
$displayedImages = isset($_SESSION['displayed_images']) ? $_SESSION['displayed_images'] : [];
$availableImages = array_diff($allImages, $displayedImages);

if (empty($availableImages)) {
    // 如果所有图像都已显示过，重置会话
    $_SESSION['displayed_images'] = [];
    $availableImages = $allImages;
}

// 随机选择一个图像ID
$randomIndex = array_rand($availableImages);
$randomImageId = $availableImages[$randomIndex];

// 获取图像路径
$sql = "SELECT path FROM images WHERE id = $randomImageId";
$result = $conn->query($sql);
$imagePath = $result->fetch_assoc()['path'];

// 记录已显示的图像ID
$_SESSION['displayed_images'][] = $randomImageId;

$conn->close();

// 显示图像
echo "<img src='$imagePath' alt='Random Image'>";
?>