FLUX image detector
Fewer than 1 in 100 original camera photos are wrongly flagged (0.6%)
Can Perspicax detect FLUX images?
Yes. Perspicax caught 96.6% of FLUX 3 images in testing. FLUX is Black Forest Labs' family of image models: some run on its API, others are open weights that anyone can run. API images carry Content Credentials; images from open-weight models often carry no label at all, so Perspicax checks the pixels.
Where these images come from
FLUX 3 Image (October 2026) runs on Black Forest Labs' API and Playground and through services such as OpenRouter and fal. The open-weight models, FLUX 3 Klein and FLUX.2 klein, run on anyone's own hardware.
Labels and watermarks
Images from Black Forest Labs' API and Playground include Content Credentials (C2PA). No Black Forest Labs invisible watermark has been confirmed, and files from open-weight models can come with no label at all.
- Content Credentials (C2PA)Live
- SynthID watermark checkSupported
What we measured
- FLUX 396.6%
Worth knowing
FLUX models come with different licences: FLUX.2 klein 4B uses Apache 2.0, and FLUX 3 Klein is free for commercial use under US$5M in revenue.
How it worksQuestions about FLUX images
Do FLUX images have Content Credentials?
From Black Forest Labs' API and Playground, yes. From open-weight FLUX models running elsewhere, often not, so a missing label tells you nothing.
Is FLUX open source?
Some of it. FLUX 3 Image is a closed API; FLUX 3 Klein and FLUX.2 klein are open-weight models under their own licences, from Apache 2.0 to non-commercial.
Which FLUX model did you test?
FLUX 3: 96.6% of its images caught, on copies collected after release. We publish a number only after we have measured it.
Can Perspicax detect images from apps built on FLUX?
Yes, if they are photo-like and fully AI-generated: it checks the image itself, whichever app made it.
Before you believe it, check it.
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