Photismos Viewer | Offline image/video lightbox gallery tool for local files

Photismos Viewer is a single, self-contained HTML file — an offline image and video review tool. You open it in a browser, point it at a folder of media on your own computer, and it renders a polished gallery with a full-screen lightbox, zoom, categories, titles, descriptions, and more. Nothing is uploaded anywhere; every file stays on your machine.

It reads directly from your folders, and it can also write back to them — adding media, renaming files, storing titles and descriptions as small text files, and setting cover images. When you're happy with a collection, it can export a standalone static website you can host or share.

Requires a Chromium browser (Chrome, Edge, Brave, etc.) — not Firefox or Safari.

Essentially, it turns your local folders of images and videos into an interactive experience similar to a live website, with image thumbnails representing folders, a navbar at the top that mirrors your folder structure, and responsive galleries with a lightbox.

I developed this tool with the help of Claude AI as a better alternative to using Windows file explorer and default photo viewing apps. It looks nicer, provides easier navigation and larger thumbnails, and handles short video clips much better.

It also has the ability to group variants of related image/video items into group slideshows, with one showing as the default and others showing when you use the hover navigation controls. I find this feature one of the most useful, as I often make multiple videos from one source image; this allows me to include variants without cluttering the gallery thumbnails with each version.

The zip download contains two html files: the Photismos Viewer, and a comprehensive User Guide. Please make sure to read through it.