How to use Google Gemini to detect AI-generated images
- By Web Desk -
- Nov 25, 2025
As the Google Gemini 3 update elevates the game with the Nano Banana Pro image generator, the images created are so realistic that it is difficult to identify whether they are AI-generated or real. Google is providing an extension that detects images with hidden watermarks.
With the recent update to Google’s Nano Banana, AI-generated images come with invisible watermarks that indicate the photo was created using a generation engine. The latest update means images are even more realistic, which makes Google’s AI detection tool all the more valuable.
Every image generated by Gemini 3 Pro is embedded with SynthID markers, according to Google. While Gemini models can detect these markers, they will not be directly visible to individuals viewing the image on their devices.
The marker is detectable using the SynthID extension in the Gemini app. If any portion of an image contains those markers, Gemini can report back with assurance that the image was created using AI.
How to detect an AI-generated image
Users can ask Gemini whether an image has been created with Nano Banana or generated with other models in general. Here’s how to check if an image is AI-generated:
- Open the Gemini app or website.
- Tap Add files +.
- Upload the suspected image.
- Ask a verification question:
- “Was this created or edited with Google AI?”
- “Is this image real?”
- “Is this AI-generated?”
Note: You can also type “@synthid” after attaching an image.
Limitations of Image Detection
Gemini can only definitively verify images created with Nano Banana Pro, as other AI generation tools, such as ChatGPT, do not use the same unique identifying watermark. Consequently, Gemini cannot be 100% certain whether an image is authentic if a different model generated it.
However, Gemini can still examine the generated image in remarkably fine detail, pointing out nuances that serve as red flags. It will highlight visual flaws, such as issues with hair blending and symmetry, while also considering the overall aesthetic appeal of the image.