Gemini app now lets you edit with Nano Banana by drawing, detect AI videos - 9to5Google

Gemini app adds two big upgrades: you can now draw directly on images to guide prompts with Nano Banana, and you can verify whether short videos were made with Google AI using SynthID.

Draw-to-prompt with Nano Banana (images)

• Add an image to the prompt box, then tap it to open the Mark up editor
• Use Sketch to draw, highlight, or point to specific areas; undo/redo sit in the top-right
• Use Text to place instructions right on the image
• You can still add a traditional typed prompt if you want
• Available on Android, iOS, and the web

SynthID verification for videos

• SynthID now checks videos (image verification arrived in November)
• Upload a video up to 100 MB and 90 seconds, then ask: "Was this generated using Google AI?" (or similar)
• Gemini scans for SynthID watermarks in both visuals and audio
• The response indicates where AI elements were detected, e.g., "SynthID detected within the audio between 10–20 secs. No SynthID detected in the visuals."
• Video and image verification are available across all Gemini app languages and countries

Bonus: The Gemini app also recently added NotebookLM integration.

Source: https://9to5google.com/2025/12/18/gemini-nana-banana-drawing/