How to Create a WordPress plugin for page loading times and SEO.This example includes features such as image lazy loading, browser caching, and minification of CSS and JavaScript.

<?php
/**
 * Plugin Name: SpeedOptimize
 * Description: A simple WordPress plugin to improve page loading times and SEO.
 * Version: 1.0
 * Author: Your Name
 */

// Enqueue the optimization scripts
function speed_optimize_enqueue_scripts() {
    // Enqueue optimized scripts
    wp_enqueue_script('optimized-scripts', plugin_dir_url(__FILE__) . 'js/optimized-scripts.js', array('jquery'), '1.0', true);

    // Add async and defer attributes to scripts
    add_filter('script_loader_tag', function ($tag, $handle) {
        if ('optimized-scripts' !== $handle) {
            return $tag;
        }
        return str_replace(' src', ' async defer src', $tag);
    }, 10, 2);
}

add_action('wp_enqueue_scripts', 'speed_optimize_enqueue_scripts');

// Enable image lazy loading
function speed_optimize_enable_lazy_loading($content) {
    return 'loading="lazy" ' . $content;
}

add_filter('the_content', 'speed_optimize_enable_lazy_loading');

// Enable browser caching
function speed_optimize_browser_caching() {
    if (!is_admin()) {
        // Set browser caching for 1 week
        header('Cache-Control: public, max-age=' . 604800);
    }
}

add_action('init', 'speed_optimize_browser_caching');

// Minify CSS and JavaScript files
function speed_optimize_minify_assets() {
    if (!is_admin()) {
        // Minify CSS
        wp_register_style('minified-style', plugin_dir_url(__FILE__) . 'css/minified-style.css');
        wp_enqueue_style('minified-style');

        // Minify JavaScript
        wp_register_script('minified-script', plugin_dir_url(__FILE__) . 'js/minified-script.js', array(), '1.0', true);
        wp_enqueue_script('minified-script');
    }
}

add_action('wp_enqueue_scripts', 'speed_optimize_minify_assets');