Istanbul's Digital Archivists Are Drowning in Duplicate Images — And the Numbers Tell a Troubling Story

Istanbul's municipal digital infrastructure holds an estimated tens of millions of image files accumulated over more than a decade of digitisation drives — and a growing share of them are exact or near-exact duplicates. That is the central problem now preoccupying archivists, IT administrators, and urban planners at institutions across the city as storage costs climb and retrieval systems slow under the weight of redundant data.

The issue has become urgent in 2026 for a specific reason: Istanbul Metropolitan Municipality's ongoing Smart City Initiative, which falls under the broader Turkey 2053 Vision framework, is pushing city departments to consolidate their digital holdings into unified platforms. When teams began auditing image libraries this spring in preparation for that migration, the scale of duplication became impossible to ignore. Departments had been independently photographing the same heritage sites, construction inspections, and infrastructure surveys for years, with no coordinated deduplication policy in place.

The Scale of the Problem in Hard Numbers

Duplicate image data is not a trivial inefficiency. Storage analysts generally estimate that unmanaged enterprise image libraries contain between 20 and 40 percent duplicate or near-duplicate files, a figure that compounds quickly when dozens of departments operate independently. For a city the size of Istanbul — with 39 districts, 16 million registered residents, and municipal departments spanning transport, heritage, emergency response, and urban renewal — even a conservative duplication rate translates into hundreds of terabytes of wasted capacity.

Cloud storage at enterprise scale currently runs at roughly 0.02 to 0.03 USD per gigabyte per month on major platforms. At that rate, 500 terabytes of redundant image data alone could cost an institution the equivalent of 120,000 to 180,000 USD annually in unnecessary storage fees — before accounting for bandwidth, indexing overhead, or the staff hours spent searching through bloated libraries. Istanbul's Fatih district planning office, which oversees one of the densest concentrations of heritage buildings in Europe, reportedly maintains photographic records stretching back to the early 2000s across multiple siloed systems, none of which have been cross-referenced for duplicates.

The Istanbul Metropolitan Municipality's Directorate of Information Technologies, headquartered near the Saraçhane administrative complex in Fatih, has been working on automated deduplication protocols since at least 2024. The approach relies on perceptual hashing — a technique that generates a compact fingerprint for each image and flags pairs that fall below a set similarity threshold. Unlike simple file-comparison tools, perceptual hashing catches duplicates even when images have been resized, recompressed, or slightly cropped, which is common in workflows where the same photograph passes through multiple departments.

Why Deduplication Matters Beyond the Server Room

The practical stakes extend well beyond IT budgets. Istanbul sits on active fault lines, and post-2023 earthquake preparedness has made accurate, retrievable photographic documentation of buildings a genuine public safety issue. The Istanbul Earthquake Risk Mitigation and Emergency Preparedness Project, known by its Turkish acronym İSMEP, has logged thousands of structural inspection photographs across vulnerable neighbourhoods from Avcılar on the European side to Pendik on the Anatolian coast. If those records are duplicated, mislabelled, or buried under redundant files, inspectors pulling up a building's history in an emergency face a slower, less reliable search.

Tourism and heritage bodies face a parallel version of the problem. The Sultanahmet Conservation Area, which draws millions of visitors annually, generates enormous volumes of photographic documentation from municipal surveyors, conservation specialists at the Istanbul Archaeological Museums, and urban renewal teams. Without a shared deduplication standard, the same mosque facade or Byzantine column capital may exist in dozens of slightly different versions across different drives, with no single authoritative image easily retrievable.

For city departments now facing the Smart City consolidation deadline, the practical next step is a phased audit: first identify all image repositories across directorates, then run automated perceptual hash comparisons to flag likely duplicates, then apply human review to ambiguous cases before deletion. Institutions holding heritage photography are advised by archivists not to delete on algorithmic judgment alone — a photograph taken at a slightly different angle or on a different date may carry independent evidentiary value even if it looks nearly identical to another. Getting that balance right, at scale, across one of Europe's largest cities, is the work now quietly underway in server rooms from Levent to Üsküdar.