Istanbul's Duplicate Image Problem: The Numbers Piling Up Behind a Digital Crisis

Istanbul's public digital infrastructure is carrying a hidden weight. Across municipal image repositories, cultural heritage documentation systems and tourism-facing platforms, an estimated 30 to 40 percent of stored visual files are functionally identical copies — duplicates that consume server capacity, slow retrieval times and quietly inflate the city's annual data management budget. The problem has a name that rarely makes headlines: duplicate image proliferation. But the numbers behind it are hard to ignore.

The timing matters. Istanbul Metropolitan Municipality, known locally by its Turkish acronym IBB, has been on a digitisation drive since 2019, accelerating the scanning and archiving of historic neighbourhood records, Bosphorus shoreline surveys and seismic vulnerability assessments in the aftermath of the February 2023 Kahramanmaraş earthquakes. That rapid ingestion of material — tens of thousands of image files per quarter across multiple departments — created fertile ground for duplication. Different teams uploading the same aerial survey photograph, heritage conservationists re-scanning documents that had already been processed, tourism bureaux repurposing press images without cross-checking central libraries: the causes are mundane, but the cumulative effect is not.

Where the Data Bottlenecks Are Forming

Two institutions illustrate the scale particularly well. The İstanbul Büyükşehir Belediyesi's Urban Transformation Directorate, which coordinates seismic retrofitting projects across high-risk districts including Avcılar and Zeytinburnu, maintains a photographic record of approximately 140,000 buildings flagged for assessment. Internal audits conducted earlier this year, according to technology procurement documents reviewed by The Daily Istanbul, identified that roughly 47,000 of those image files existed in two or more identical or near-identical copies within the same database environment. Storage costs for the directorate's primary data centre, located in Başakşehir, have risen accordingly.

The second pressure point is cultural heritage. The İstanbul Arkeoloji Müzeleri — the Istanbul Archaeological Museums complex near Sultanahmet — digitised more than 200,000 artefact photographs between 2021 and 2025 as part of a European Union co-funded preservation grant. Archivists working on the project have noted, without specifying precise figures publicly, that the absence of a centralised deduplication protocol meant multiple departments archived identical high-resolution scans under different file names and catalogue numbers. The result: a repository that is technically comprehensive but operationally bloated.

Tourism compounds everything. Platforms serving Istanbul's 20-million-plus annual visitor base — including the official Go Türkiye portal and district municipality websites covering areas like Beyoğlu and Fatih — routinely pull from overlapping image libraries. Lighthouse and drone photographs of the Galata Tower, for instance, exist across at least six separate public-facing content management systems, each holding multiple versions. A 2025 report by the Turkish Informatics Foundation, TBD, estimated that public-sector data duplication across Turkey's ten largest cities costs the equivalent of hundreds of millions of lira annually in unnecessary storage licensing alone — a figure made more painful by the lira's sustained purchasing-power erosion over the past four years.

What Deduplication Actually Requires

Solving the problem is less technically exotic than administrators sometimes suggest. Perceptual hashing — an algorithmic method that assigns a fingerprint to each image and flags near-matches regardless of file name — is standard practice in private-sector media libraries and has been deployed successfully in public archives in cities including Amsterdam and Seoul. The barrier in Istanbul is less about technology and more about inter-departmental coordination: the IBB's IT infrastructure spans dozens of semi-autonomous directorates, each with procurement autonomy and separate vendor contracts.

Procurement notices published on the Public Procurement Authority platform, known as KİK, show the IBB tendered for a unified digital asset management system in March 2026, with contract award expected by September. If that timeline holds, the deduplication process could begin before the end of the year. For heritage institutions like the Archaeological Museums, the path is slower — EU grant conditions governing the 2021–2025 digitisation project require data retention protocols that complicate any deletion or consolidation workflow.

For now, city administrators, archivists working along İstiklal Caddesi's cultural institutions and urban planners mapping risk zones from Kadıköy to Esenyurt are all working around the same structural inefficiency. The images exist. Many of them exist two or three times over. And until the September tender delivers results, the storage meters keep running.