Roundcube IMAP on Debian Linux PHP mime types to be read in HTML $75USD

This project has to do with reading remote in-line images in an email.
such that photos and images pop up or are read through embedded HTML emails.
This is a brand new install, latest version of Roundcibe

You will be to configuring the following files and making sure that the browser can read Apache driven extensions:
/var/www/roundcube/defaults.inc.php
/var/www/roundcube/config.inc.php

You will need to understand PHP 7.4, Aapche2 and Roundcube

// Mimetypes supported by the browser.
// Attachments of these types will open in a preview window.
// Either a comma-separated list or an array. Default list includes:
// text/plain,text/html,
// image/jpeg,image/gif,image/png,image/bmp,image/tiff,image/webp,
// application/x-javascript,application/pdf,application/x-shockwave-flash
$config['client_mimetypes'] = null;

// Path to a local mime magic database file for PHPs finfo extension.
// Set to null if the default path should be used.
$config['mime_magic'] = null;

// Absolute path to a local mime.types mapping table file.
// This is used to derive mime-types from the filename extension or vice versa.
// Such a file is usually part of the apache webserver. If you don't find a file named mime.types on your system,
// download it from http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
$config['mime_types'] = null;