Zurich's Digital Archives Are Full of Duplicate Images — Officials and Experts Are Finally Taking It Seriously

Redundant image files are quietly eating through storage budgets and slowing down public-facing digital services across Zurich's municipal and academic institutions — and the people responsible for fixing it are no longer treating the problem as routine housekeeping.

The issue has surfaced repeatedly in discussions at the Stadthaus on Stadthausquai, where city IT administrators have been reviewing digital asset management across several departments. The core problem: the same image, photograph, or graphic gets uploaded, renamed, and stored multiple times across disconnected systems, compounding costs and complicating retrieval. For a city that has staked much of its administrative modernisation agenda on digitisation, the inefficiency is an awkward contradiction.

The timing matters. Zurich's municipal IT directorate is partway through a multi-year consolidation of public-sector data infrastructure, a project connected to the federal government's broader E-Government Switzerland strategy, which sets 2027 as a target year for key interoperability benchmarks. Wasted storage is not merely an aesthetic concern — it creates compliance headaches and inflates procurement costs at a moment when city budgets are already under pressure from rising construction costs tied to the Wohnungsnot housing crisis.

What the Experts Are Saying

At ETH Zurich, researchers working in the university's Data Science group have examined the duplicate-image problem as part of wider work on institutional data quality. The challenge, as specialists in the field describe it, is not technical so much as organisational: departments acquire their own storage solutions, workflows diverge, and without a centralised deduplication policy, redundancy compounds year over year. ETH's main campus on Rämistrasse handles research image libraries running into the hundreds of terabytes, making the stakes considerably higher than in a typical administrative context.

The Swiss Federal Archives, based in Bern, published guidelines in 2024 recommending that public institutions adopt automated hash-based deduplication tools before migrating legacy content to long-term storage. Those guidelines have informed conversations at Zurich's Stadtarchiv on Neumarkt, where archivists have been assessing their own digitisation backlog. The Stadtarchiv holds physical and digital holdings spanning several centuries; its staff have flagged that scanning workflows — where the same physical document is scanned multiple times by different contractors — generate a disproportionate share of duplicate files.

Specialists in digital asset management point to a practical benchmark: industry analyses have consistently found that 20 to 40 percent of files in unmanaged institutional image repositories are exact or near-exact duplicates. For a mid-sized European city administration, that can translate to tens of thousands of francs in avoidable annual storage costs, depending on whether the institution relies on on-premises servers or cloud contracts. Zurich's city IT procurement, reviewed annually through the municipal budget process, does not publicly itemise storage expenditure by category, but the directorate has confirmed it is evaluating deduplication tooling as part of its 2026 infrastructure review cycle.

What Comes Next for City Institutions

Pressure is building from more than one direction. The cantonal data protection authority, the Datenschutzbeauftragter des Kantons Zürich, has signalled that unnecessarily retained duplicate files can complicate data subject requests under cantonal privacy law — because an institution obliged to delete or provide an image must first be certain it has found every copy. That legal dimension has sharpened the interest of city legal counsel in a problem that might otherwise have stayed in the IT department.

For institutions looking at near-term action, specialists recommend a phased approach: first, an audit of existing repositories using perceptual hashing tools that can identify near-duplicate images even when file names differ; second, a governance decision on which copy becomes the authoritative master file; third, automated prevention at the point of upload. Several Swiss municipal IT teams, including those in Basel-Stadt, have begun piloting this kind of pipeline since early 2025.

Zurich's own pilot, if approved in the autumn budget round, would likely begin with the Stadtarchiv and the communications department before extending to larger data stores. The city has not announced a timeline, but the 2027 E-Government deadline is concentrating minds. Getting duplicate images under control is, in the bluntest terms, a precondition for the more ambitious digital services Zurich has been promising its 450,000 residents for years.