Deep dive

How SafPix works

SafPix is a small kit of free, private photo tools — a forensic checker for spotting AI fakes and edits (plus a reverse-image-search hand-off to check whether a photo appears elsewhere), plus quick tools to clean, blur, stamp and sanity-check your own pictures. Every one of them runs entirely in your browser. Nothing is ever uploaded to a server.

One toolkit, five jobs

SafPix started as a real-vs-fake checker and grew into a small set of photo-safety tools. Each one does a single job well, and each runs 100% on your device — no upload, no account, no cost.

The first tool — Check — is the one with the forensic engine. Here's exactly how it reads an image.

Inside Check: the signal categories

When you drop an image into Check, a battery of independent passes runs in your browser — 18 forensic signals across the categories below, plus an in-browser AI detector. Forensic analysis is a game of weighted evidence, not a single oracle: no individual signal is bulletproof, but several independent signals pointing the same way is a pattern worth trusting. Here's what each category reveals.

1
Digital Origin
Reads embedded metadata + Content Credentials

Every real camera embeds a digital fingerprint into every photo it takes — the camera make, model, date, and sometimes GPS coordinates. SafPix reads this fingerprint and checks it against a database of known camera signatures and AI generator tags.

If the metadata says Midjourney or Stable Diffusion, the image is instantly flagged. If it says Apple iPhone 15 Pro with a valid date, that's strong evidence of a real capture. If the metadata is completely stripped — that's suspicious on its own.

SafPix also reads Content Credentials (C2PA) — a tamper-evident "nutrition label" that newer cameras, Adobe apps and AI tools now attach to images. When it's present and the signature is intact, it's the strongest evidence there is: it can cryptographically prove a photo came from a real camera, or that it was generated by a specific AI tool. SafPix lets a valid Content Credential override every other signal — and flags it if the signature has been broken.

CatchesSigned Content Credentials (C2PA); AI images with generator tags; unedited camera photos; photos edited in Photoshop or Lightroom
MissesAI images with stripped metadata; screenshots; photos shared through social media (platforms strip metadata)
2
Compression Integrity
Detects edits, splices & composites

When someone pastes a face onto another photo, adds an object, or composites from multiple sources, the edited region compresses differently from the rest of the image. SafPix's compression analysis detects these inconsistencies and renders them as a visual heatmap — green means consistent, red means something was changed.

Honest limitation: This signal is strongest against edited and composited photos. Pure AI-generated images have uniform compression (they were only saved once), so this signal alone won't catch them — but the other four will.

CatchesPhotoshop composites, face swaps, object insertions, heavy filter applications
MissesPure AI generations with uniform compression; re-saved images
3
Sensor Noise
A physics fingerprint that's hard to fake

Every physical camera sensor produces a unique noise signature — random fluctuations from the electronics and photon physics. This noise is consistent across a real photo and has characteristics that vary by camera. SafPix isolates and analyzes this noise layer using established signal-processing techniques.

Many AI-generated images either have no real sensor noise (suspiciously "clean") or carry artificial noise that's inconsistent across the frame. It's one of our better signals for spotting pure AI generation — but we're honest that the newest generators are getting better at faking convincing grain, so SafPix weighs it alongside everything else rather than treating it as the last word.

CatchesAI images (too clean); composited regions (inconsistent noise); heavily denoised photos
MissesAI images with carefully added synthetic noise; very low-resolution images
4
Texture & Structure
Finds unnaturally smooth regions

Real photos have fine micro-texture everywhere — skin pores, hair strands, fabric weave, background detail. AI generators often produce unnaturally smooth regions, especially on faces and skin, because they optimize for visual plausibility rather than pixel-level realism.

SafPix maps the texture density across the image and flags regions that are too smooth to come from a real camera. You can see this yourself in the Texture overlay — real photos have detail everywhere, AI images have conspicuous "painted" zones.

CatchesAI portraits with smooth skin; over-filtered photos; AI backgrounds
MissesAI images with added grain; naturally low-contrast scenes
5
Pixel Forensics
Statistics + an in-browser AI detector

The fifth pass runs a battery of statistical checks that look for patterns unique to AI generation — including color characteristics, structural symmetry, and pixel-level uniformity that real cameras don't produce. Each check alone is a weak signal, but when several fire together, the compound signature is strong evidence.

This category also includes an open-source AI-image detector that runs entirely in your browser — a small neural model trained on millions of real and AI-generated images. We're honest about its ceiling: no public AI detector is right every time, and the best ones sit around 80% on freshly released generators. So SafPix treats the model as one weighted vote, not a verdict — and when its different views of an image disagree, it abstains and says "unclear" rather than guessing. We keep adding checks as generators evolve.

CatchesCommon generator outputs, over-saturated AI aesthetics, compound AI signatures, images a trained AI-detection model flags
MissesWell-tuned generators with realistic color profiles; heavily post-processed AI images

How the signals combine

Each signal scores 0–100. SafPix combines them using a weighting system that adapts based on what evidence is available — giving more weight to the signals that matter most for each image. When multiple signals flag the same image, compound penalties strengthen the verdict. When an image carries intact Content Credentials, that cryptographic proof takes priority over the statistical signals — and when the evidence genuinely conflicts, SafPix would rather tell you it's unclear than force a confident-but-wrong answer.

A single weak signal could be noise. Three signals all saying "something's off" is a pattern. SafPix trusts the pattern — and abstains when there isn't one.

Most single-model detectors give you one percentage. When it's wrong, you can't tell why. SafPix runs 18 independent signals across these categories — plus the in-browser AI detector — with plain-English explanations and visual overlays you can toggle and inspect yourself.

The limits — honestly

We'd rather tell you what we can't catch than sell you a false promise.

A note on responsibility: SafPix is informational. A "clear" score means all signals look consistent with a real photograph — strong evidence, not proof. Always combine SafPix with other context: a live video call, a second photo from a different angle, reverse image search, and your own instincts.

Have a photo you're not sure about?

Drop it in. You'll have an answer in seconds — a clear sentence telling you what we found and what it means. No signup, no upload to servers, no guesswork.

Check a photo now →