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

Sydney's planning and property databases are riddled with duplicate images — the same photograph filed dozens of times across development applications, heritage registers and council asset portals — and the systems built to catch and remove them are running years behind comparable cities. The problem, long treated as a back-office nuisance, is now drawing scrutiny from open-data advocates and urban planners who argue that cluttered, unreliable visual records slow approval times and mislead prospective buyers and renters.

The timing matters. The NSW government is pushing hard on housing supply, with Premier Chris Minns facing pressure to accelerate development approvals across Western Sydney and inner-ring suburbs. A contaminated image record in the NSW Planning Portal — the centralised system through which thousands of development applications flow each year — doesn't just create storage headaches. It can delay automated assessment tools that rely on clean visual data to flag non-compliant builds or missing documentation.

What Sydney Is Actually Doing

The Department of Planning, Housing and Infrastructure has been rolling out incremental fixes to the NSW Planning Portal since a 2024 audit identified duplicate asset uploads as a systemic issue. The City of Sydney Council, which covers the CBD and inner suburbs from Pyrmont to Zetland, introduced a mandatory file-naming protocol for DA lodgements in January 2025, designed to prevent identical images from being submitted under different file names. Blacktown City Council in Western Sydney, which processes one of the highest volumes of residential DAs in the state, has been piloting an automated deduplication tool as part of a broader digital transformation project that began in mid-2025.

Neither program is finished. Council staff familiar with the Portal's back-end have described the deduplication backlog as substantial, though the department has not publicly released figures on how many duplicate files currently sit in the system. Property information platform PropTrack estimated in a 2025 industry briefing that duplicate or mismatched imagery affects a meaningful share of listings that pass through government-linked databases — though it stopped short of a precise national figure. The NSW Spatial Digital Twin, a state government initiative that integrates land-use and building data across Greater Sydney, lists image-data integrity as one of its outstanding technical challenges in its published roadmap.

How Singapore, London and New York Handle It

Other global cities with comparable property and planning volumes have moved faster. Singapore's Urban Redevelopment Authority introduced automated image-hash verification across its development control portal in 2022, meaning duplicate photographs are flagged and rejected at the point of upload rather than after lodgement. The result, according to URA's own published data, was a reduction in image-related resubmission requests within the first 12 months of operation.

London's Planning London Datahub, run through the Greater London Authority, has integrated deduplication checks with its AI-assisted case management system since late 2023. New York City's Department of Buildings overhauled its DOB NOW portal in stages between 2021 and 2024, and now runs a daily automated sweep that compares uploaded images against a hash database before they enter the public record. Both cities treat the problem as an infrastructure issue rather than an administrative one — meaning the fix is built into the pipeline, not patched on afterwards.

Sydney's approach so far has been more fragmented. Because planning responsibilities are split between the state government and 33 separate local government areas across Greater Sydney, there is no single authority with the mandate — or the budget — to impose a uniform image-management standard. The City of Sydney and Blacktown pilots are exactly that: pilots, running independently, without a confirmed timeline for state-wide rollout.

For anyone lodging a development application in suburbs like Parramatta, Liverpool or the fast-growing Macquarie Park corridor, the practical advice is straightforward: use unique, clearly labelled file names for every image, avoid submitting the same photograph in multiple formats, and check the NSW Planning Portal's own lodgement guidelines, which were last updated in March 2026. Developers working on larger projects should consider requesting a pre-lodgement meeting with the relevant council's digital services team — several councils have begun offering these specifically to catch documentation errors before they enter the formal queue.