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Why we store embeddings instead of images

David Okafor

David Okafor

Senior Engineer

March 2026
9 min read
Why we store embeddings instead of images

9 min

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Engineering
David Okafor

David Okafor

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Every face recognition system makes a fundamental architectural decision at enrollment time: do you store the raw photo, or do you store only the mathematical representation of the face — the embedding? The choice sounds technical, but its implications are deeply legal, ethical, and reputational. At IntelliFace, we made this decision before we wrote our first line of production code: we never store photos. Here is why, and how it works.

What is a face embedding?

When our face service processes an enrollment photo, DeepFace with the SFace model runs the image through a deep convolutional neural network. The network produces a 128-dimensional floating-point vector — a sequence of 128 numbers that encode the spatial relationships between facial landmarks. This vector is the embedding. Critically, you cannot reconstruct a recognizable face image from this vector. It is a one-way mathematical transformation, similar in principle to a cryptographic hash. The original photo is discarded immediately after the embedding is generated.

  • Storage size: a raw JPEG face crop is ~80KB; an embedding is 512 bytes — 160× smaller
  • Irreversibility: no known algorithm can reconstruct a recognizable face from the embedding alone
  • Legal classification: under GDPR Article 9, biometric templates used for identification are special category data — but the legal risk is substantially lower when raw images are not retained
  • Breach impact: if embeddings are leaked, they are useless to an attacker without the matching inference model and the same model version
  • Portability: embeddings are model-version-specific — migrating to a new model requires re-enrollment, preventing silent data misuse
"

"Storing embeddings instead of photos is the architectural equivalent of hashing passwords. It is not just a privacy best practice — it is the only responsible approach for biometric data."

Pro tip

All IntelliFace embeddings are additionally encrypted at rest using AES-256 and are scoped to the tenant — our own engineers cannot access a customer's embeddings without going through an audited break-glass process. This architecture has been reviewed and approved by external GDPR auditors.

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David Okafor

Written by

David Okafor

Senior Engineer at IntelliFace

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