Prague removes thousands of duplicate images from city databases this week

Prague's city administration confirmed this week that a structured audit of its digital image repositories has uncovered tens of thousands of duplicate photograph files spread across municipal databases, triggering an urgent cleanup effort that administrators say will take until at least the end of September 2026 to complete. The problem, long acknowledged informally inside Magistrát hlavního města Prahy — the Prague City Hall on Mariánské náměstí — has now been formally classified as a priority data governance issue.

The timing matters. Prague has spent the past two years migrating content from legacy systems into a unified digital asset management platform intended to serve everything from planning department archives to the tourism marketing materials produced by Prague City Tourism, the city's official promotional agency headquartered near Staroměstské náměstí. Duplicate images did not simply clog storage. They introduced version-control failures, meaning planners and communications officers were sometimes working from outdated or mismatched photographs of neighbourhoods earmarked for redevelopment — including areas around Smíchov and the Holešovice waterfront, both under active rezoning discussions.

What the Audit Found, and Where

The audit, carried out during the final two weeks of June by the city's IT directorate in cooperation with the municipal data office, identified duplicate image rates exceeding 30 percent in at least two of the primary repositories examined. The worst affected was the internal planning archive, where photographs of sites in Žižkov and Vinohrady had been uploaded multiple times across different project folders, sometimes in slightly different resolutions, making automated deduplication tools ineffective without human review. Prague City Tourism's own content library showed a lower duplication rate — closer to 12 percent — but because that library feeds directly into the PragoAd media distribution system used by regional partners across Central Europe, even a small percentage of wrong or repeated images carries outsized consequences.

Storage costs are not trivial. Municipal cloud storage contracts, renegotiated in early 2025 as part of the city's five-year digital strategy, are billed in part by volume. City council budget documents from March 2026 placed the annual spend on municipal data storage infrastructure at roughly 28 million Czech crowns. Administrators have not yet published a specific figure for projected savings from the deduplication effort, but the data office indicated in internal correspondence — copies of which were reviewed by The Daily Prague — that redundant files currently consume an estimated 15 to 18 percent of total storage capacity across the audited systems.

Practical Steps and What Comes Next

The city's IT directorate is now deploying a two-stage remediation process. The first stage, running through July, uses automated hash-matching software to flag exact duplicates for deletion without manual intervention. The second stage, scheduled for August and September, will require human review of near-duplicate images — photographs taken at the same location on the same date but with minor exposure or framing differences — particularly for legally sensitive planning records. Staff at the Odbor informatiky, the city's informatics department, have been allocated additional hours specifically for this review cycle.

For Prague residents and businesses that interact with city platforms, the immediate practical consequence is that some image galleries on the Prague.eu portal may temporarily display reduced photo selections or placeholder images while files are verified. The city's communications office said the disruption should be minimal but acknowledged that certain neighbourhood pages — including those covering Nové Město and parts of Praha 7 — may see gaps during the peak audit weeks in late July.

Longer term, the city intends to introduce mandatory metadata tagging for all new image uploads from August 1, a standard already adopted by Vienna's municipal digital office and recommended by the European Commission's 2024 guidelines on public sector data management. Whether Prague's departments will comply consistently is a question the data office will begin tracking formally with quarterly compliance reports starting in the fourth quarter of 2026.