Zoomify

Zoomify is a technology and service that enables high-resolution images to be viewed interactively on the web by streaming only the portions of an image that are needed. It is commonly used for art catalogs, maps, and architectural photography, where viewers can zoom into fine details without downloading the entire file.

The core technique is a tiled image pyramid. The source image is processed into multiple zoom levels, and each level is split into small square tiles. A metadata file describes the number of levels, tile size, and tile locations. The Zoomify viewer (historically Flash, later HTML5/JavaScript) requests tiles as the user pans and zooms, assembling them on the client side.

Usage and features: The system is designed for embedding in web pages and content management workflows. It provides pan and zoom controls, thumbnails, and sometimes annotations or hotspots. The viewer caches tiles to reduce bandwidth and can adapt to different screen sizes. Accessibility and performance depend on the deployment; modern implementations emphasize HTML5 without Flash.

History and status: Zoomify originated as a technology for distributing very large images and has been adopted by museums, libraries, and archives worldwide. It contributed to the popularity of deep-zoom tiled image viewing and influenced later standards and tools. Licensing and hosting options vary by product version and deployment.