Copenhagen's Duplicate Image Problem: What the City Must Decide Next

Copenhagen's municipal digital archive holds an estimated 340,000 photographs — and a growing share of them are duplicates. The city's IT and Culture Administration flagged the problem formally in a working document circulated in May 2026, identifying redundant image files across at least three separate platforms used by Copenhagen Municipality, the Copenhagen City Archives at Stadsarkivet on Jagtvej, and the public-facing portal VisitCopenhagen. Now the question is what to do about it, and who decides.

The issue matters now because the municipality is midway through a broader digitisation push under its 2024–2028 Digital Copenhagen strategy, which committed 180 million kroner over four years to consolidate public records, improve data quality, and make city assets easier for residents and journalists to access. Duplicate images inflate storage costs, create confusion about which version of a photograph carries the correct metadata and licensing terms, and slow down the search tools that planners, journalists, and neighbourhood associations rely on daily. Getting this wrong is not a minor administrative headache — it can mean the wrong image of a neighbourhood ends up attached to a planning application or a heritage listing.

Where the Bottlenecks Are

The duplication problem is concentrated in two areas. First, the archive at Stadsarkivet, which physically sits near Nørrebroparken, holds digitised historical photographs — many scanned multiple times over the past decade as equipment improved, leaving parallel high-resolution and low-resolution copies in separate folders with near-identical file names. Second, the redevelopment documentation for Sydhavn, the large harbour district south of Fisketorvet shopping centre, generated thousands of site photographs between 2019 and 2025, submitted by multiple contractors who used different naming conventions. No single office held authority to deduplicate them.

Teknik- og Miljøforvaltningen, the city's Technical and Environmental Administration, is the lead body on the Sydhavn material. Stadsarkivet operates under Kultur- og Fritidsforvaltningen, the Culture and Leisure Administration. Because the photographs cross administrative boundaries, neither unit has acted unilaterally. That jurisdictional gap is precisely what the May working document recommended closing — by designating a single data steward role with cross-directorate authority before the end of the third quarter of 2026.

The Decisions Ahead

Three choices are coming before city officials before autumn. The first is technical: whether to deploy automated deduplication software, which can match identical or near-identical image files and flag them for human review, or to rely on manual audit by archival staff. Automated tools available on the European municipal market in 2026 typically cost between 150,000 and 400,000 kroner for a mid-sized city licence, with ongoing maintenance. Manual review at Stadsarkivet's current staffing levels would take roughly 18 months, according to the administration's internal timeline estimate.

The second decision is about licensing. Many photographs in the city's archive were contributed by residents, neighbourhood councils like those in Vesterbro and Nørrebro, and third-party photographers under terms that differ file by file. A deduplication process risks discarding one copy while retaining another with different rights attached. The city's legal unit must determine which metadata field takes precedence when copies conflict — a question that has implications well beyond photography, touching how Copenhagen handles duplicate documents across its entire Open Data portal.

The third, and politically most visible, decision is about transparency. Civil society groups including the urban heritage organisation Historisk Atlas København have publicly pushed for the deduplicated archive to be made fully searchable and free to download. The city has not yet committed to that standard. A public consultation is expected in September 2026, timed to coincide with European Heritage Days, which gives residents and organisations a formal window to register their preferences before any final policy is locked in.

For anyone with a stake in the outcome — community groups, researchers, journalists, or residents who have donated photographs to city collections — the September consultation is the moment to engage. Submissions can be made through the city's official portal at kk.dk. The data steward appointment, expected by late August, will signal which direction the administration is leaning before that conversation even formally opens.