Copenhagen's Digital Archives Tackle a Growing Duplicate Image Crisis This Week

Copenhagen's main municipal archive, Stadsarkivet, confirmed this week that it has launched a dedicated duplicate-image replacement programme targeting tens of thousands of redundant digital files accumulated across city departments since at least 2018. The effort, which began in earnest on Monday, July 1, involves automated deduplication software scanning shared drives used by the City of Copenhagen's Technical and Environmental Administration.

The timing matters. Municipal IT departments across the city have been under pressure to cut operational costs ahead of the 2027 budget cycle, and unchecked image duplication has emerged as one of the more correctable drains on server capacity. Stadsarkivet estimates — based on an internal audit completed in May — that duplicate or near-duplicate image files account for a disproportionate share of active storage use in at least four major city departments. That audit has not yet been made public, but its conclusions were confirmed to The Daily Copenhagen by the archive's administrative communications office this week.

What's Actually Being Replaced — and Where

The immediate focus is on digital assets linked to urban planning and infrastructure documentation. Files tied to development projects in Ørestad and along Havnegade have been flagged as particularly cluttered, with multiple versions of the same building-survey photographs saved under different filenames across overlapping project folders. Workers at the Copenhagen City Hall on Rådhuspladsen have been briefed on new file-naming protocols that take effect July 7.

The city is also working with the Royal Danish Library — Det Kongelige Bibliotek, based at Søren Kierkegaards Plads — to cross-reference publicly accessible image databases against the municipal archive's holdings. The goal is to retire low-quality or redundant versions and ensure that the canonical, highest-resolution image is the one preserved and indexed. Librarians at the Black Diamond building, the library's striking harbourfront extension, have been part of working-group meetings since early June.

Local photographers are watching closely. The Danish Photographers' Association, Dansk Fotografforbund, flagged the issue as early as 2024, pointing out that duplicate images in public archives sometimes mean that rights-managed originals are quietly displaced by unauthorised copies. The association, which has offices in central Copenhagen, is in discussions with Stadsarkivet about a verification layer that would check licensing metadata before any image is formally designated as the replacement master file.

The Scale of the Problem

Duplicate image bloat is not unique to Copenhagen, but the city's digital infrastructure has grown rapidly. The municipality's total digital storage footprint grew by roughly 34 percent between 2020 and 2024, according to figures published in the City of Copenhagen's annual IT report for 2024. A portion of that growth reflects legitimate expansion — more CCTV feeds, more drone surveys of construction sites in Nordhavn, more digitised historical records. But IT managers have been candid in internal communications, shared with this newspaper, that a significant slice of that growth reflects poor file hygiene rather than genuine new content.

The deduplication software now being deployed was procured through a joint tender with the City of Aarhus earlier this year, at a combined contract value of approximately 4.2 million kroner. Copenhagen's share of that contract has not been separately itemised in public procurement records reviewed this week.

Residents and community organisations that submit photographs to city portals — including the neighbourhood consultation platform Bliv Hørt, used widely in districts like Nørrebro and Amager — will see a new upload interface by September 1 that flags potential duplicates before a file is accepted. City planners say the change will reduce manual review time and make community submissions easier to retrieve in future project searches.

For anyone who regularly submits images to municipal portals or contributes to local documentation projects, the practical advice from Stadsarkivet is straightforward: use consistent file names that include a date and project reference, avoid re-uploading corrected versions without deleting the original, and check whether the portal's new duplicate-detection tool has flagged your file before completing a submission. Full guidance will be posted to the City of Copenhagen's official website at kk.dk when the updated upload system goes live in September.