Sydney Is Quietly Becoming a Leader in Duplicate Image Replacement — But the Race Is Global

Sydney's State Library of New South Wales flagged the problem internally more than two years ago: thousands of digitised records contained duplicate or near-identical images filed under different catalogue entries, creating search dead-ends and eroding the credibility of its public-facing collections portal. The fix, it turned out, was neither cheap nor quick. But as of mid-2026, the library's collections team has worked through more than 140,000 image records using a combination of perceptual hashing software and manual curatorial review — a process that has become a loose benchmark for similar institutions across the country.

The timing matters. Sydney recorded its hottest June since 1859 this week, a fact that has librarians and archivists thinking harder about digitisation as physical collections face increased climate risk. More immediately, the explosion of AI-generated content over the past 18 months has made duplicate and near-duplicate imagery a live problem for newsrooms, government agencies, real estate listings platforms, and heritage bodies alike. The question is no longer whether a city needs a coherent approach to duplicate image management — it's whether the approach can scale fast enough to be useful.

What Sydney Is Actually Doing

The State Library's effort is the most visible, but it is far from the only one. The City of Sydney Council has been running a parallel audit of images used across its planning and development application portal, a system that handles tens of thousands of DA submissions annually through the NSW Planning Portal. Council officers identified that duplicated and recycled property images — some reused across unrelated DA submissions in suburbs including Surry Hills, Glebe, and Redfern — were causing delays in assessment workflows. The council declined to put a dollar figure on the remediation cost, but the audit began in the third quarter of 2025 and is ongoing.

On the commercial side, Domain, the property listings platform headquartered in the Sydney CBD, has disclosed in investor materials that it deploys automated duplicate detection across its image pipeline, processing millions of property photographs each month. The company has pointed to this capability as a competitive differentiator in a market where the same property photograph routinely appears across multiple listings, sometimes for properties in different suburbs entirely — a known issue across Parramatta, Liverpool, and the Hills District.

The National Museum of Australia in Canberra, though not a Sydney body, has been collaborating with the Powerhouse Museum in Ultimo on shared deduplication standards for the GLAM sector — galleries, libraries, archives, and museums — following a joint working group established in February 2025. The Powerhouse, which relocated its main collection activities to its new Parramatta campus, has used that transition as a forcing function to clean image metadata at scale before ingestion into new systems.

How Sydney Compares Globally

London's Victoria and Albert Museum completed a comparable image deduplication project across roughly 1.2 million digital objects in 2024, using open-source tooling developed partly in partnership with the Alan Turing Institute. Toronto Public Library has a smaller collection but moved earlier, beginning systematic deduplication in 2022 with a focus on photographic negatives from the 20th century. Sydney institutions have generally moved later but with more centralised coordination, partly because the NSW government's digital records policy, updated in March 2025, now requires agencies to document image provenance and flag duplicates before migrating collections to cloud storage.

Singapore's National Heritage Board is often cited as the Asia-Pacific benchmark, having completed a six-year image rationalisation project in 2023 across four national collecting institutions. Sydney's GLAM sector is not yet at that level of coordination, though the Powerhouse-National Museum working group is a step in that direction.

For individuals dealing with duplicate images on a smaller scale — photographers, small businesses, community organisations — the NSW Small Business Commission has listed several image management tools in its digital readiness resources, updated in June 2026. Residents who submit imagery through government portals, including the NSW Planning Portal, are advised to use original photographs rather than stock or recycled images to avoid processing delays. The State Library's digitised collections portal, accessible at sl.nsw.gov.au, now includes a public-facing duplicate-report function, something Toronto introduced in 2023 and London is still working toward.