'show_html' => false, // show (filtered) text/html attachments (and oEmbed HTML etc.). Doesn't affect AJAX calls.
'show_thumbs' => true, // show thumbnails in notice lists for uploaded images, and photos and videos linked remotely that provide oEmbed info
'process_links' => true, // check linked resources for embeddable photos and videos; this will hit referenced external web sites when processing new messages.
+ 'extblacklist' => [
+ 'php' => 'phps',
+ 'exe' => false, // this would deny any uploads to keep the "exe" file extension
+ ],
),
'thumbnail' =>
array('crop' => false, // overridden to true if thumb height === null