Zurich Takes a Methodical Approach to Duplicate Image Replacement — and Other Cities Are Watching

Zurich's city administration confirmed earlier this year that its central digital asset repository — maintained by the Stadtarchiv Zürich and used across departments from urban planning to tourism promotion — had accumulated tens of thousands of duplicate or near-duplicate image files over the past decade. The problem is not unique to Zurich, but the city's response is drawing attention for its structured, procurement-driven fix rather than an ad-hoc cleanup.

The urgency is real. Municipal digital repositories across Europe have expanded dramatically since roughly 2018, when most city governments accelerated their digital-first communications strategies. That growth accelerated again during the pandemic years, as departments uploaded documentation, event photography and infrastructure records with little central oversight. The result, in Zurich as elsewhere, is databases clogged with redundant files that slow workflows, inflate cloud storage costs and — critically — create legal exposure when outdated or rights-unclear images are published by mistake.

What Zurich Is Actually Doing

The Stadtarchiv Zürich, located on Neumarkt in the Altstadt district, has been piloting a semi-automated deduplication workflow since the second quarter of 2025. The system uses perceptual hashing — a technique that identifies visually similar images even when file names differ — to flag duplicates for human review before deletion. Unlike a fully automated purge, Zurich's approach requires a trained archivist to approve removals, a deliberate choice given the archival value of some images that might appear identical but carry different provenance metadata.

Zurich Tourismus, the city's official destination marketing body on Stampfenbachstrasse, operates a separate image library for promotional use and has run its own parallel deduplication project since January 2026. The two organisations are not yet fully coordinated, which archivists have described in general terms as an area for improvement — though no formal merger of the two systems has been announced.

The city's IT department, Amt für Informatik, has budgeted for a unified digital asset management platform as part of the broader Digitale Verwaltung Zürich programme, though procurement documents reviewed by The Daily Zurich do not specify a go-live date beyond a general 2027 target window.

How Zurich Compares

Other mid-to-large European cities have tackled the same problem with varying degrees of ambition. Amsterdam's Stadsarchief began a large-scale digital deduplication effort in 2023, applying automated tools across roughly 1.4 million files with minimal manual review — a faster but riskier approach that resulted in a small number of incorrectly deleted records that had to be restored from backup. Vienna's Wiener Stadt- und Landesarchiv opted for a vendor-managed solution through a three-year contract awarded in late 2024, trading internal control for speed. In North America, Toronto's City Clerk's Office has publicly documented its digital records management challenges, citing duplicated imagery across departmental servers as a recurring audit finding.

Zurich's insistence on human sign-off at the deletion stage sits closer to the Vienna model in its caution, though without the full outsourcing. For a city where direct democratic accountability is embedded in governance culture — and where a single botched records deletion could theoretically trigger a municipal referendum demand — that conservatism is arguably fitting.

Storage costs provide another lens. Enterprise cloud storage in Switzerland typically runs higher than in neighbouring Germany or the Netherlands, partly due to data sovereignty requirements under Swiss law that restrict where public-sector data can be hosted. That premium gives Zurich a financial incentive to resolve its duplicate problem that cities with cheaper hosting options may lack.

For residents, the practical upshot is gradual. Zürcher who use the city's open data portal on opendata.swiss may notice improved image metadata and fewer broken or redundant file links over the coming 18 months as the deduplication work progresses. Journalists and researchers who rely on the Stadtarchiv's holdings are the most direct beneficiaries: cleaner catalogues mean faster search results and fewer dead ends. The city has not set a formal completion target, but the Digitale Verwaltung Zürich programme is subject to annual reporting to the Stadtrat, which means the cleanup's progress will eventually be a matter of public record.