ext_localconf.php

<?php
defined('TYPO3_MODE') || die();

$boot = function ($_EXTKEY) {
    /** @var \TYPO3\CMS\Extbase\SignalSlot\Dispatcher $signalSlotDispatcher */
    $signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class);

    // Hook into \TYPO3\CMS\Core\Resource\ResourceStorage
    $signalSlotDispatcher->connect(
        \TYPO3\CMS\Core\Resource\ResourceStorage::class,
        \TYPO3\CMS\Core\Resource\ResourceStorageInterface::SIGNAL_SanitizeFileName,
        \Causal\ImageAutoresize\Slots\FileUpload::class,
        \Causal\ImageAutoresize\Slots\FileUpload::SIGNAL_SanitizeFileName
    );
    $signalSlotDispatcher->connect(
        \TYPO3\CMS\Core\Resource\ResourceStorage::class,
        \TYPO3\CMS\Core\Resource\ResourceStorageInterface::SIGNAL_PostFileReplace,
        \Causal\ImageAutoresize\Slots\FileUpload::class,
        \Causal\ImageAutoresize\Slots\FileUpload::SIGNAL_PostFileReplace
    );
    $signalSlotDispatcher->connect(
        \TYPO3\CMS\Core\Resource\ResourceStorage::class,
        \TYPO3\CMS\Core\Resource\ResourceStorageInterface::SIGNAL_PreFileAdd,
        \Causal\ImageAutoresize\Slots\FileUpload::class,
        \Causal\ImageAutoresize\Slots\FileUpload::SIGNAL_PreFileAdd
    );
    $signalSlotDispatcher->connect(
        \TYPO3\CMS\Core\Resource\ResourceStorage::class,
        \TYPO3\CMS\Core\Resource\ResourceStorageInterface::SIGNAL_PostFileAdd,
        \Causal\ImageAutoresize\Slots\FileUpload::class,
        \Causal\ImageAutoresize\Slots\FileUpload::SIGNAL_PopulateMetadata
    );
    $signalSlotDispatcher->connect(
        \TYPO3\CMS\Extensionmanager\ViewHelpers\ProcessAvailableActionsViewHelper::class,
        \TYPO3\CMS\Extensionmanager\ViewHelpers\ProcessAvailableActionsViewHelper::SIGNAL_ProcessActions,
        \Causal\ImageAutoresize\Slots\ExtensionManager::class,
        \Causal\ImageAutoresize\Slots\ExtensionManager::SIGNAL_ProcessActions
    );

    // Uploads in uploads/ of good old non-FAL files
    $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['processUpload'][] = \Causal\ImageAutoresize\Hooks\FileUploadHook::class;

    $extensionName = \TYPO3\CMS\Core\Utility\GeneralUtility::underscoredToUpperCamelCase($_EXTKEY);
    $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['scheduler']['tasks'][\Causal\ImageAutoresize\Task\BatchResizeTask::class] = [
        'extension' => $_EXTKEY,
        'title' => 'LLL:EXT:' . $_EXTKEY . '/Resources/Private/Language/locallang_mod.xlf:batchResizeTask.name',
        'description' => 'LLL:EXT:' . $_EXTKEY . '/Resources/Private/Language/locallang_mod.xlf:batchResizeTask.description',
        'additionalFields' => \Causal\ImageAutoresize\Task\BatchResizeAdditionalFieldProvider::class,
    ];

};

$boot($_EXTKEY);
unset($boot);