use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use SimonVomEyser\CommonMarkExtension\LazyImageExtension;
$environment = new Environment([]);
$environment->addExtension(new CommonMarkCoreExtension())
            ->addExtension(new LazyImageExtension());
$converter = new MarkdownConverter($environment);
$html = $converter->convert('![alt text](/path/to/image.jpg)');

$environment = new Environment([
    // ... other config
    'lazy_image' => [
        'strip_src' => true, // remove the "src" to add it later via js, optional
        'html_class' => 'lozad', // the class that should be added, optional
        'data_attribute' => 'src', // how the data attribute is named that provides the source to get picked up by js, optional
    ]
]);
$environment->addExtension(new CommonMarkCoreExtension())
    ->addExtension(new LazyImageExtension());
$converter = new MarkdownConverter($environment);
$html = $converter->convert('![alt text](/path/to/image.jpg)');