PHP开发中如何优化图片压缩和优化加载

<?php
function compressImage($source, $destination, $quality) {
    $info = getimagesize($source);
    
    if ($info['mime'] == 'image/jpeg') {
        $image = imagecreatefromjpeg($source);
    } elseif ($info['mime'] == 'image/png') {
        $image = imagecreatefrompng($source);
    }
    
    imagejpeg($image, $destination, $quality);
    
    return $destination;
}

// 压缩图片
$sourceImage = 'path/to/source/image.jpg';
$destinationImage = 'path/to/destination/image.jpg';

$compressedImage = compressImage($sourceImage, $destinationImage, 80);
echo '压缩后的图片路径：' . $compressedImage;
?>

// 引入 Lazy Load 插件的 js 文件

document.addEventListener("DOMContentLoaded", function() {
    var lazyImages = [].slice.call(document.querySelectorAll("img.lazy"));

    if ("IntersectionObserver" in window) {
        let lazyImageObserver = new IntersectionObserver(function(entries, observer) {
            entries.forEach(function(entry) {
                if (entry.isIntersecting) {
                    let lazyImage = entry.target;
                    lazyImage.src = lazyImage.dataset.src;
                    lazyImage.classList.remove("lazy");
                    lazyImageObserver.unobserve(lazyImage);
                }
            });
        });

        lazyImages.forEach(function(lazyImage) {
            lazyImageObserver.observe(lazyImage);
        });
    }
});