Istanbul's Duplicate Image Problem: The Key Decisions That Will Shape the City's Visual Identity

Istanbul's municipal digital archive has reached a breaking point. The İstanbul Büyükşehir Belediyesi — the metropolitan municipality — is sitting on a library of public-record photographs that, according to internal administrative discussions this spring, contains a significant proportion of duplicate and near-duplicate images accumulated across more than a decade of digitisation drives. The immediate question is not storage cost alone. It is about which images survive, which get erased, and who decides.

The timing matters. The municipality's ongoing Smart City initiative, launched under Mayor Ekrem İmamoğlu's administration, is pushing to make archival footage and photography publicly accessible through an open-data portal by the end of 2026. Before that portal goes live, every duplicate must be assessed. Delete the wrong version of a photograph — the higher-resolution scan, or the one with correct metadata tagging — and you can quietly hollow out the historical record of a neighbourhood that no longer looks the way it did when the shutter clicked.

What the Archive Actually Contains — and Why It's Complicated

The duplication problem did not arrive overnight. It is the residue of at least three separate digitisation campaigns: a 2013 project centred on Sultanahmet and the Historic Peninsula, a 2018 Bosphorus coastal survey commissioned in partnership with the İstanbul Kültür ve Sanat Vakfı (IKSV), and a pandemic-era 2020 scan of Kapalıçarşı — the Grand Bazaar — and its surrounding hans that was carried out by volunteers from the Mimar Sinan Fine Arts University photography department. Each project ran its own naming conventions and metadata standards. When files were later consolidated into a single repository, the system could not reliably distinguish an original from a copy, or a slightly better exposure from a degraded duplicate.

Heritage preservation adds a layer of urgency that pure data management does not. The Tarihi Yarımada — the Historic Peninsula, a UNESCO World Heritage Site — is one of the most photographed urban areas in Europe, yet its pre-2010 street-level photographic record is thinner than it appears. Duplicates distort that thinness: a search of the archive for Çemberlitaş or Divanyolu Caddesi returns dozens of results, but many are the same image uploaded under different filenames, giving a false impression of richness.

Automated deduplication software can resolve the obvious cases — identical pixel arrays, same file size. The harder category is near-duplicates: two photographs taken seconds apart from slightly different angles, or the same scene scanned twice at different resolutions. Here, an algorithm cannot make a curatorial decision. A human archivist must.

The Decisions Ahead — and the Organisations That Must Make Them

Three bodies will drive what happens next. The İBB's Kültürel Miras ve Müzecilik Daire Başkanlığı — the metropolitan directorate responsible for cultural heritage — must establish a formal retention policy before the open-data portal launches. The directorate has not yet published a public draft of that policy. The İstanbul Planlama Ajansı, the city's urban planning agency on Meclis-i Mebusan Caddesi in Beyoğlu, is separately compiling a geospatial image layer for the post-2023 earthquake risk mapping project, and its team needs clean, non-redundant visual data to overlay on structural vulnerability assessments.

Then there is the question of cost. Cloud storage for large image archives is not free. Industry benchmarks put archival-grade cold storage at roughly 0.004 US dollars per gigabyte per month for major providers; at scale, a poorly curated archive running to hundreds of terabytes becomes a recurring line item that compounds annually. Municipalities in Athens and Madrid have both undertaken public deduplication reviews in the past four years, publishing their methodology documents openly — Istanbul's administrators are understood to be examining those precedents.

The practical path forward involves three steps in sequence: an audit of existing metadata standards across all three digitisation projects, a public consultation period during which heritage organisations including IKSV can flag images of particular cultural significance, and a final technical review before any deletion is executed. Archivists working with the Kapalıçarşı Esnaf ve Sanatkârlar Odası — the Grand Bazaar traders' association — have previously expressed interest in retaining veto rights over images documenting their specific sections of the market. Whether that interest translates into formal representation in the review process is one of the unresolved questions heading into the autumn.

The portal deadline of December 2026 is fixed. The decisions are not.