Gemini & Nano Banana Detector: How to Check an Image
To check a Gemini or Nano Banana image, use Google’s SynthID Detector to look for a watermark, then inspect any Content Credentials. If the origin is still unclear, compare an AI image checker score with the original post and the details in the picture.
1. Get the original image
Download the file from its creator or first upload when possible. Keep that copy and note the source URL before editing it. A screenshot gives you the visible picture, but does not copy the original file’s embedded creation record. If you are checking a social post, keep the caption too: a real photograph can be shared with a false claim.
2. Check with Google SynthID Detector
Open Google SynthID Detector and select your file. Google has expanded this portal from a limited professional trial to public access. It checks supported watermarks in images, video, and audio, including content from Google and participating partners.
You can also sign in at Gemini, attach one image, and ask whether Google AI created or edited it. Read the verification response for a watermark finding. A general description of how a picture looks answers a different question from a watermark check.
The two entry points have different coverage. Google’s Gemini help page says its SynthID verification recognizes Google-created content; the standalone portal also supports participating partners. Use the tool’s reported finding to identify what it detected, rather than assuming every result means Nano Banana was the source.
3. Read Content Credentials
Content Credentials record a file’s origin and editing history. Check the original at Content Credentials Verify or inspect available credentials through Gemini. Look for the named creator or tool, the creation action, and later edits. A camera photograph with an AI edit is a different case from a scene generated entirely from a prompt.
4. Compare the signals
- Watermark detected: read which supported provider or creation process the tool identifies.
- Credentials available: follow the recorded creation and editing history, and compare it with the caption.
- No record found: check the source and run an AI image detector to gather another signal.
Our free AI image checker analyzes image patterns and returns an AI confidence score. It does not decode SynthID or identify the exact generator. For a worked comparison, see our detector comparison with documented image files.
Can you check a screenshot of a Gemini image?
Yes. SynthID is embedded in the content and designed to resist common changes such as cropping and compression. That does not guarantee a readable mark in every altered copy. Keep the image as clear as possible and compare with the original when available. Our screenshot and JPEG experiment shows how two image detectors scored the same scenes in different files; it does not test SynthID.
Sources
Common questions
How do I check whether a picture was made with Nano Banana?
Start with Google SynthID Detector or, after signing in, upload the image to Gemini and ask whether Google AI created or edited it. Read any available Content Credentials, then compare the result with the original source.
Is SynthID Detector available to the public?
Yes. Google has opened its SynthID Detector portal to everyone. It checks for supported SynthID watermarks in images, videos, and audio.
Does a missing SynthID watermark mean a photo is real?
No. An image can come from a generator that does not use SynthID. Look for creation records, compare other detector signals, and trace the image to its source.
Can AI Detector identify the exact Gemini model?
AI Detector returns an AI confidence score. It does not identify a specific model or read a SynthID watermark. Use Google’s verification tools to check the watermark itself.
Check any image in under 3 seconds
AI Detector scores an image and never stores it.
