You can customize the website using the settings icons in the top right corner of the /list page.
Clicking the cog icon brings you to the rest of the settings.
On the /settings page you can adjust both the thumbnail size and the theme of the page. In addition to that you can also change the default sorting behavior when loading the website and enter a special access code that you get by signing up to the ambientCG Patreon page. This will give you access to new asses several weeks before anyone else.