Knockout-Lite/app/BbCode/Tag/Image.php

<?php

namespace App\BbCode\Tag;

use Knockout\BbCode\Tag\TagInterface;
use Knockout\BbCode\Tokenizer\Tag as TokenTag;

class Image implements TagInterface
{

    public function format(TokenTag $tokenTag): string
    {
        $link = $tokenTag->getText();
        if (!preg_match('!^https?://[a-z0-9\-@:.,_&+%#?/=]+$!i', $link)) {
            $unknownTag = new Unknown();
            return $unknownTag->format($tokenTag);
        }

        return '<img src="' . $link . '" />';
    }

    public function getName(): string
    {
        return 'img';
    }

    public function getOriginalText(TokenTag $tokenTag): string
    {
        return "[{$this->getName()}]{$tokenTag->getText()}[/{$this->getName()}";
    }
}