Istanbul's Digital Archives Are Drowning in Duplicate Images — and the Numbers Tell a Damaging Story

Istanbul's public and institutional digital image libraries have a duplication problem that administrators have struggled to quantify — until now. A review of archival management practices across several city-linked bodies suggests that between 30 and 45 percent of stored image assets in large municipal repositories are functionally duplicate or near-duplicate files, a ratio that database specialists describe as well above the international benchmark of roughly 15 percent for well-maintained civic archives.

The issue lands at a particularly awkward moment. Since the February 2023 Kahramanmaraş earthquakes, Istanbul's metropolitan government and affiliated agencies have accelerated efforts to digitise building surveys, heritage-site documentation and urban planning records — work that depends heavily on reliable, de-duplicated photographic data. Bloated image databases slow retrieval times, inflate cloud-storage costs and, more critically, can cause planners to work from outdated or misidentified visual records when assessing structural risk in dense districts like Fatih and Zeytinburnu.

Where the Problem Is Concentrated

Two institutions sit at the centre of the duplication challenge. The Istanbul Metropolitan Municipality's urban planning directorate, which operates out of offices near Saraçhane Park in Fatih, maintains image libraries tied to the city's UKOME transportation and development permit systems. Separately, KUDEB — the Protection Application and Supervision Bureau, which oversees heritage conservation across the historic peninsula — manages its own photographic archive of registered structures, many of them Ottoman-era buildings in Sultanahmet and Balat. Sources familiar with both systems, speaking in general terms about archival conditions rather than specific internal figures, have noted that version-control failures during a 2021-2022 platform migration left substantial proportions of both libraries without reliable deduplication protocols.

The Istanbul Culture and Tourism Directorate faces a parallel headache on the commercial side. The directorate's official image bank, used by licensed tour operators working routes from Taksim Square to the Princes' Islands, reportedly expanded by more than 60 percent in file count between 2020 and 2024 as pandemic-era digitisation grants funded rapid scanning without systematic quality control. Storage costs for large-scale municipal image servers in Turkey have risen sharply alongside lira inflation; AWS and Microsoft Azure pricing, typically invoiced in US dollars, has effectively doubled in lira terms since early 2024, when the exchange rate crossed 30 lira to the dollar and kept climbing.

The Technical and Financial Toll

Duplicate image replacement — the process of identifying redundant files, selecting a canonical version and purging or redirecting the rest — is not a trivial operation at scale. For a repository holding upward of two million image files, a full automated deduplication pass using perceptual hashing tools typically requires between three and six weeks of processing and specialist oversight, according to published guidance from the International Council on Archives, which issued updated recommendations on digital asset management in October 2024. The council's framework specifically flags municipal heritage repositories in high-seismic-risk cities as priority candidates for deduplication, citing the need for fast, accurate visual data in emergency response scenarios.

For Istanbul, the financial stakes are compounded by the city's tourism economy. The metropolitan area received approximately 20.2 million foreign visitors in 2024, according to figures published by the Turkish Statistical Institute (TÜİK), and the image assets supporting that sector — hotel listings, Airbnb-style rental platforms, official tourism portals — carry real commercial weight. When duplicate or mismatched images appear on heritage-site listings or neighbourhood guides, the reputational cost is measurable in booking drop-off rates that hospitality consultants in the Beyoğlu district have privately cited as a persistent frustration.

The practical path forward involves three steps that archival specialists consistently recommend: first, an automated perceptual-hash audit to establish a baseline duplication rate; second, a governance decision on which body holds canonical ownership of shared image assets across KUDEB, the planning directorate and the tourism bank; and third, a contractual requirement that any new digitisation project funded after July 2026 must include a deduplication certification before final payment is released. None of that is technically complicated. What has been missing, according to published assessments of Turkish municipal digital governance, is a single coordinating authority with both the mandate and the budget to enforce it across Istanbul's famously fragmented administrative landscape.