Tokyo's Duplicate Image Problem: What Officials, Experts and Key Figures Are Saying

Tokyo's municipal data managers have a growing headache: thousands of duplicate and degraded images are embedded across the city's official digital platforms, from the Tokyo Metropolitan Government's tourism portal to ward-level administrative systems, undermining public trust and wasting storage budgets that run into the hundreds of millions of yen annually.

The issue has sharpened this summer as inbound tourism hits record volumes — foreign arrivals at Narita and Haneda combined exceeded 3.5 million in May 2026 alone, according to figures published by the Japan Tourism Agency — putting unprecedented pressure on multilingual web portals to display accurate, high-resolution imagery of venues, transport links and accommodation. When a traveller searching for directions to Senso-ji in Asakusa or a hotel near Shinjuku Station finds a blurry duplicate photo from 2019, the practical consequences are immediate.

What the Officials Are Saying

Within the Tokyo Metropolitan Government's Bureau of General Affairs, internal working groups have been examining automated deduplication tools since at least April 2026. Senior administrators — speaking in the context of a broader digitisation review tied to the metropolitan government's GovTech Tokyo initiative, launched in fiscal 2023 — have flagged image management as a category needing standardised protocols. GovTech Tokyo, headquartered near Yurakucho, coordinates digital reform across all 23 special wards and has a stated mandate to reduce redundant data infrastructure.

Experts at the University of Tokyo's Graduate School of Interdisciplinary Information Studies in Hongo have pointed to the structural problem: public-sector image databases in Japan were built incrementally, ward by ward, without a unified taxonomy. When Shibuya Ward upgraded its event listings platform in 2024 and Minato Ward overhauled its business licensing portal in early 2025, neither migration included systematic duplicate-image audits, leaving inherited copies buried inside content management systems.

Ryuichi Matsumoto, Japan's minister for digital affairs as of mid-2026, has made consolidation of public digital assets a stated priority under the Digital Agency's roadmap — though the agency's published materials do not yet specify binding timelines for image-database reform at the metropolitan level.

Tools, Costs and Next Steps

Technology vendors working with Tokyo's public sector cite perceptual hashing and machine-learning-based similarity scoring as the two dominant technical approaches for identifying duplicates at scale. One index — the open-source pHash library — can process roughly 10,000 images per minute on standard server hardware, a threshold relevant to databases like the Tokyo Convention & Visitors Bureau's media library, which reportedly holds tens of thousands of licensed photographs of sites from Odaiba to Yanaka.

The financial stakes are real. Cloud storage costs for unoptimised image repositories — containing duplicates, outdated files and uncompressed originals — can represent 20 to 40 percent of a public agency's total data infrastructure spending, according to general estimates cited in digital-government literature. For Tokyo's 23 wards collectively, that overhead is not trivial.

Practitioners advising ward governments recommend a three-stage approach: first, an automated audit using hashing tools to flag candidate duplicates; second, human review by designated content administrators — a role that does not yet exist as a formal civil-service classification in Tokyo; third, replacement with standardised, accessible-format images meeting the Web Content Accessibility Guidelines 2.1 AA standard, which the Japanese government adopted as a reference benchmark in its 2022 accessibility guidelines.

The Minato Ward Cultural Foundation's digital archive team, based near Azabu-Juban, has been piloting one such review process since March 2026 across its collection of neighbourhood event photographs. The results — not yet published — are expected to inform a wider proposal to the Bureau of General Affairs later this fiscal year.

For residents and organisations that submit images to ward portals — a category that includes everything from Nakameguro riverside festival coordinators to Akihabara electronics retailers listing on business directories — the practical advice from digital consultants is consistent: submit images in JPEG or WebP format at no less than 1,200 pixels on the long edge, keep file names descriptive and unique, and retain originals offline. That discipline at the point of upload is far cheaper than a deduplication audit after the fact.