fembooru/ext/handle_ico/theme.php

<?php declare(strict_types=1);

class IcoFileHandlerTheme extends Themelet
{
    public function display_image(Page $page, Image $image)
    {
        $ilink = $image->get_image_link();
        $html = "
			<img id='main_image' class='shm-main-image' alt='main image' src='$ilink'
			data-width='{$image->width}' data-height='{$image->height}'>
		";
        $page->add_block(new Block("Image", $html, "main", 10));
    }
}