>>146279
it is the uploader, and proof is this screen
https://world2ch.net/uploader/warota.php?goingto=settings
archive if they remove https://web.archive.org/web/20250521171734/https://world2ch.net/uploader/warota.php?goingto=settings

previews are only an option with Heyuri additions to it, it's all documented on github
https://github.com/Heyuri/Uploader/commit/99723f5ad2790d650cd3b31847a27c3b93092e47

This is what a real zurubon uploader looks like
https://ch723.net/uploader/upload.php
環境設定 links to the old version for the settings page

They removed the link to the settings panel altogether on their site (maybe because they couldn't configure server to properly generate the thumbnails), but it's there