Sydney's Duplicate Image Problem: How the City Stacks Up Against London, Singapore and New York

Sydney's public archives hold millions of digitised photographs, maps and planning documents — and a significant proportion of them appear more than once. Duplicate images clog search results, inflate storage costs and, in at least one documented case, caused a Western Sydney council to mis-sequence heritage photographs during a planning review. The problem is not unique to Sydney, but the city's response is measurably behind that of comparable global institutions.

The timing matters. NSW is mid-way through the largest rezoning program in a generation under the government's Transport Oriented Development reforms, and heritage records tied to train corridors through suburbs like Sydenham, Marrickville and Macquarie Park are being pulled into planning submissions at speed. When digital asset libraries contain duplicate or mislabelled images, the errors travel downstream into legal documents and development applications.

What Sydney's institutions are actually doing

The State Library of New South Wales, based on Macquarie Street in the CBD, completed a partial audit of its digital image catalogue in 2024 and identified duplication rates in specific photographic collections, according to a review published on the Library's website. The Library runs a metadata remediation program — a structured effort to tag, deduplicate and cross-reference images — but the program covers only a subset of the 900,000-plus items in its digital holdings. City of Sydney Council's open-data portal, which houses planning photographs and streetscape records stretching back to the late 19th century, uses a different classification system again, creating interoperability gaps when researchers move between the two repositories.

The NSW Department of Planning and Environment's ePlanning portal holds a separate bank of site-condition images uploaded by applicants and assessors. There is no automatic deduplication layer on that system. Duplicate images submitted across multiple development applications for the same site — common in high-density corridors like Green Square and Waterloo — accumulate without flags.

Compare that with Singapore's National Archives, which deployed a machine-learning deduplication tool across its digitised collection in 2022 as part of the Smart Nation initiative. The tool reduced catalogued duplicates by a reported 34 percent within 12 months, according to the National Archives of Singapore's 2023 annual report. London's Wellcome Collection completed a similar AI-assisted audit of its image library in late 2023. New York's NYPL Labs, the digital-innovation arm of the New York Public Library, has published open-source deduplication scripts used by at least eleven other public institutions since 2021.

The cost of falling behind

Cloud storage is not cheap. AWS S3 standard storage — the most common tier used by Australian government agencies — costs roughly $0.025 per gigabyte per month at current Sydney region pricing. A library or council holding even 50 terabytes of unaudited, duplicate-heavy image files pays for redundant data every billing cycle. Across NSW government agencies combined, the figure is difficult to pin down publicly, but the logic is straightforward: deduplication pays for itself.

The City of Parramatta Council launched a records-management modernisation project in late 2025 covering planning, heritage and community services files. Council documentation listed image deduplication as a component of that project, with an expected completion date in the second half of 2026. That puts Parramatta ahead of most peer councils in Greater Sydney, though still roughly three years behind Singapore's national-level rollout.

For researchers, planners and heritage practitioners working day-to-day in Sydney, the practical advice is blunt: cross-check any image pulled from the ePlanning portal or a council open-data source against the State Library's catalogue before submitting it in a formal document. Use reverse-image search tools, including Google Images and TinEye, to identify whether a photograph has already been used in a conflicting context elsewhere in the public record. The NSW government has not yet announced a unified deduplication standard for public digital assets, though consultation on updated digital recordkeeping guidelines under the State Records Act 1998 is reportedly underway. Until a system-wide solution arrives, the verification burden sits with the individual practitioner.