Hong Kong's Duplicate Image Problem: The Numbers Driving a Digital Clean-Up Across the City's Archives

Hong Kong's public and private institutions are sitting on tens of millions of duplicate digital images — redundant files accumulated across decades of fragmented storage systems — and a growing coalition of archivists, IT managers and records compliance officers is now pushing to quantify, and fix, the problem. The numbers are striking.

Digital asset management firms operating out of Cyberport and the Hong Kong Science and Technology Parks Corporation have reported that duplicate or near-duplicate images typically account for between 30 and 45 percent of total image file storage in large institutional libraries. For organisations that have migrated data multiple times — think government bureaus that shifted systems after 2020, or media companies that consolidated servers — that figure can climb higher. Redundant files do not just waste disk space; under Hong Kong's Personal Data (Privacy) Ordinance, retaining unnecessary copies of images that contain identifiable individuals creates measurable legal exposure.

Scale Across the City's Key Institutions

The Hong Kong Public Libraries system, administered by the Leisure and Cultural Services Department and operating across more than 70 branch locations from Sham Shui Po to Tseung Kwan O, began a digital asset audit in early 2025. While the department has not published final results, procurement documents filed with the Government Logistics Department in the third quarter of 2025 referenced a cataloguing contract covering an initial tranche of approximately 2.4 million digitised image files, with deduplication cited as a primary objective.

At the city's universities, the scale is similar. The Hong Kong Baptist University Library at Shaw Campus in Kowloon Tong and the University of Hong Kong's Main Library on Pokfulam Road have both invested in automated deduplication pipelines in the past two years. Industry benchmarks from global digital preservation bodies suggest that for every 100 terabytes of archival image data, between 15 and 22 terabytes typically consist of exact or perceptual duplicates — files that look identical to the human eye even when pixel-level hashing shows minor compression differences.

Commercial stakes are also rising. Hong Kong's advertising and media sector, concentrated around Wan Chai's Lockhart Road corridor and the cluster of production houses in Kwun Tong Industrial Area, pays for cloud storage priced in US dollars. At current market rates for enterprise-tier object storage, a 10-terabyte reduction in redundant image data translates to an annual saving of roughly HK$15,000 to HK$22,000 per account — modest for a single company, but meaningful across an industry that collectively manages petabyte-scale libraries.

Why 2026 Is the Crunch Year

Two regulatory timelines are converging. The updated Code of Practice on Human Resource Management under the Personal Data (Privacy) Ordinance, which took effect in January 2026, tightened requirements on data minimisation. Separately, the Innovation, Technology and Industry Bureau's Digital Government Blueprint update, published in late 2025, set a target for all Policy Bureau systems to complete data hygiene audits by December 31, 2026. Duplicate image removal is explicitly listed as one measurable output under that programme.

Detection technology has matured to match the regulatory pressure. Perceptual hashing algorithms — which identify visually similar images even after resizing, cropping or recompression — now process around 50,000 images per minute on commodity server hardware, according to published benchmarks from open-source tools including ImageDedup and Microsoft's PhotoDNA documentation. That speed makes full-library scans practical for the first time for mid-sized Hong Kong organisations that previously could only sample their archives.

For institutions still working through their own audits, compliance officers point to three immediate steps: run a baseline hash-based scan to establish a duplicate count before the year-end Bureau deadline; segment results by file creation date to identify migration-era duplication spikes; and document the retention decision for any image touching identifiable personal data before deletion. The deadline is six months away. The data, for most organisations, already exists. The work is in reading it.