---
title: "Legacy: thumbnails via headless.php (ImageViewHelper)"
manual: "Headless Content Blocks"
version: "main"
permalink: "https://docs.typo3.org/permalink/netzbewegung/nb-headless-content-blocks:legacy-thumbnails-via-headless-php-imageviewhelper@main"
source: "_archive/LegacyHeadlessPhpThumbnails.rst"
rendered: "2026-09-22T03:00:33+00:00"
noindex: true
---

# Legacy: thumbnails via headless.php (ImageViewHelper) {#legacy-thumbnails-via-headless-php-imageviewhelper}

> Status: **SUPERSEDED by declarative image variants** — for File fields of a Content Block, replace this pattern with [headless.yaml](https://docs.typo3.org/permalink/netzbewegung/nb-headless-content-blocks:define-image-variants@main). Kept as the historical reference for migrating existing blocks; production sites carry many copies of this file (13 on the site this extension was built for). One case is **not** yet replaceable: images inside Collection items — see the [migration guide](https://docs.typo3.org/permalink/netzbewegung/nb-headless-content-blocks:migrate-legacy-thumbnails-to-headless-yaml@main).

## The pattern {#the-pattern}

`your_extension/ContentBlocks/ContentElements/your-content-block-element/headless.php` with thumbnail generation through the Fluid `ImageViewHelper`:

```php
<?php

use TYPO3\CMS\Fluid\ViewHelpers\Uri\ImageViewHelper;

$generateThumbnail = function (array $arguments): string {
    if (array_key_exists('absolute', $arguments) === false) {
        $arguments['absolute'] = true;
    }

    $imageViewHelper = new ImageViewHelper();

    foreach ($imageViewHelper->prepareArguments() as $argumentKey => $argumentDefinition) {
        if (array_key_exists($argumentKey, $arguments) === false) {
            $arguments[$argumentKey] = $argumentDefinition->getDefaultValue();
        }
    }

    $imageViewHelper->setArguments($arguments);

    return $imageViewHelper->initializeArgumentsAndRender();

};

foreach ($data['items'] ?? [] as $itemKey => $item) {

    if ($item['image']) {
        $image = $item['image'];

        $data['items'][$itemKey]['image']['thumbnails'] = [
            'mobile' => $generateThumbnail(['src' => $image['id'], 'treatIdAsReference' => true, 'width' => 320]),
            'desktop' => $generateThumbnail(['src' => $image['id'], 'treatIdAsReference' => true, 'width' => 800]),
        ];
    }
}

return $data;
```

## Why it was replaced {#why-it-was-replaced}

-   Every Content Block repeated the same generator with different widths — pure duplication across site packages.
-   Driving a Fluid ViewHelper from PHP for URL generation is an abuse of the ViewHelper API (no DI, awkward argument filling, hidden dependencies).
-   Nothing about the variants was declarative or reviewable — widths hid in PHP closures.

The declarative replacement produces the same `thumbnails` map next to the frozen `id/alt/title/publicUrl` shape: [Define image variants](https://docs.typo3.org/permalink/netzbewegung/nb-headless-content-blocks:define-image-variants@main).