Zürich's Digital Archive Crisis: The Hidden Cost of Duplicate Images Clogging City Systems

Zurich's public institutions collectively store an estimated 340 terabytes of duplicate image data across municipal servers, according to internal IT audits circulated among cantonal departments this spring. The figure, compiled by the city's Digital Services unit at Stadthaus Zürich on Stadthausquai, has prompted urgent reviews of how organisations from ETH Zurich to the Stadtarchiv manage their digital asset libraries — and who is paying for the redundancy.

The timing matters. Since January 2026, the federal government's updated Data Economy Act has required all cantonal bodies to publish annual digital storage efficiency reports. For a city that has positioned itself as a European technology hub, the gap between ambition and practice is proving embarrassing. Server space in Swiss data centres ran at roughly CHF 0.18 per gigabyte per month as of Q1 2026 — modest by unit, punishing at scale. At that rate, Zurich's duplicate image problem costs the public sector an estimated CHF 61,000 every month for storage alone, before accounting for bandwidth, backup cycles or staff time spent locating the correct version of an asset.

Where the Numbers Come From

The Stadtarchiv Zürich on Neumarkt, which digitised over 1.2 million historical photographs between 2019 and 2024, found during a February 2026 internal review that roughly 22 percent of its online image library consisted of near-identical duplicates — same photograph, different file name, sometimes different resolution. That is approximately 264,000 redundant files. The archive's IT team had been relying on manual tagging rather than automated deduplication software, a process that the review described as unsustainable given the planned digitisation of a further 400,000 physical items over the next three years.

ETH Zurich's library system on Rämistrasse presents a different dimension of the same problem. The university's open-access research repository, which serves institutions across the German-speaking world, logged 18 million image asset requests in 2025. Internal benchmarking found that automated hash-comparison tools — standard in commercial content management systems — could reduce the repository's active image index by up to 31 percent without losing a single unique file. The library has budgeted CHF 420,000 for a deduplication overhaul scheduled to begin in September 2026, funded partly through the Swiss National Science Foundation's infrastructure support programme.

What Deduplication Actually Fixes

The practical consequences of duplicate images extend well beyond storage bills. Zürich Tourismus, headquartered near Hauptbahnhof, acknowledged in its 2025 annual report that its digital media portal had accumulated over 47,000 destination photographs since 2015, of which staff manually estimated a third were redundant variants — slightly different crops, identical subjects, different compression levels. Platform load times for the tourism portal's press centre ran at an average 4.3 seconds per page in 2025, against an industry benchmark of under 2 seconds. The organisation is trialling AI-assisted image recognition software from a Zurich-based startup in the Technopark on Technoparkstrasse, with preliminary results suggesting a 28 percent reduction in indexed assets during the pilot phase that ran from March through May this year.

For the UBS digital communications team, which inherited a substantial portion of Credit Suisse's brand asset library following the 2023 merger, the challenge took on an additional legal dimension. Licensing records for several thousand images transferred from the old Credit Suisse archive were incomplete, meaning duplicates could not simply be deleted — each had to be individually verified before removal. The bank's internal asset management team processed approximately 9,000 such files between June 2025 and March 2026.

City IT officials recommend that any Zurich organisation managing more than 50,000 digital image files adopt a formal deduplication audit cycle, running hash-based comparison tools at minimum once per calendar year. The canton's Digital Services unit plans to publish a shared-use procurement framework by October 2026, which would allow smaller municipal bodies — district libraries, neighbourhood Gemeinschaftszentren, local cultural archives — to access enterprise deduplication tools at negotiated rates rather than absorbing full licence costs individually. Institutions waiting for that framework should, in the meantime, freeze new bulk uploads to existing repositories and document storage baseline figures now, so efficiency gains can be measured accurately once automated tools go live.