Imbricalt Viewer

Alt text used to be locked in a CMS. Now it lives inside the image file. The Imbricalt Viewer Chrome extension scans any webpage, detects images processed by Imbricalt, and displays their alt text as a floating label — no backend, no API, no configuration.

How It Works

Imbricalt is an AI alt text generator that embeds descriptions directly into JPEG and PNG image metadata (IPTC/XMP fields). Each processed image carries an imbricalt:processed signature inside the file itself. The Imbricalt Viewer extension reads this signature in two stages:

Stage 1 — Metadata scan. When you visit a page, the extension fetches each JPEG and PNG image and parses its embedded XMP metadata. If the imbricalt:processed signature is found, the alt text is extracted from the dc:description or Iptc4xmpCore:AltTextAccessibility field and displayed as a floating overlay near the image.

Stage 2 — Perceptual hash (Fallback). If the metadata has been stripped (for example, by image-optimisation pipelines, CDNs, or social media platforms), the extension computes a perceptual hash (pHash) of the image using the same DCT-based algorithm that runs on Imbricalt servers. This 64-bit hash is sent to the Imbricalt API, which finds the closest match via Hamming distance. Each image ever processed through Imbricalt is indexed and findable through this method.

Key Features