Technology

Photographs are evidence only if faking them is hard

A photo uploaded from a gallery proves that a photo exists. Everything else about it is an assumption.

June 24, 2026  ·  The Renny team

Draw documentation in home improvement is largely photographic. The industry treats a photograph as proof of work, and for most purposes that is a reasonable working assumption, because faking one is inconvenient rather than impossible.

Inconvenient is a weak security property. It holds until someone has a strong incentive, which is exactly the circumstance where the evidence matters.

What a plain upload actually establishes

• That an image file was submitted. That is the whole of it.
• Not when it was taken. File metadata is trivially editable and often stripped.
• Not where. Same.
• Not that it shows this property, or this job, or work done under this loan.
• Not that it was not taken from a previous project, or another property, or a search engine.

What raises the bar

Three properties, in increasing order of difficulty, and worth naming precisely rather than gesturing at:

• Capture in context. The photograph is taken inside the flow, attached to the specific scope line item it evidences, rather than uploaded in a batch afterwards. This alone eliminates most casual reuse, because a reused photo has to be attached to a plausible line item.
• Fingerprinting at capture. A hash computed at the moment of capture, so the image relied upon later can be proven identical to the image submitted. This does not prove the image is honest, but it removes any argument about substitution after the fact.
• Device attestation and provenance. Platform attestation confirming the image came from a genuine, unmodified app on a real device, with time and location signed by hardware rather than asserted by software. This is what actually makes fabrication expensive.

Say which of these you have

The third requires a native mobile application and platform attestation services. It is a substantial piece of work, and any platform that has it will tell you specifically. Any platform that describes "secure photo capture" without distinguishing these levels is describing the first.

"Secure photo capture" is not a claim. Ask which of the three levels it means.

Renny does the first two today. The third is on our roadmap and needs a native application, and we would rather write that here than let a lender assume otherwise and find out during diligence.