Nano Banana 2 Background Remove
Remove backgrounds from any image with real alpha transparency using Nano Banana 2 (Google Gemini 3.1 Flash Image).
Unlike traditional background removal tools (rembg, remove.bg, BiRefNet), this uses triangulation matting — the same image is rendered on white and black backgrounds, then mathematically accurate per-pixel alpha values are computed. This produces superior results for:
- Semi-transparent elements (glass, smoke, hair, shadows)
- Clean anti-aliased edges without halos
- Accurate color recovery in translucent areas
How it works
- Your input image is fitted to the closest Nano Banana 2 output format (aspect ratio + resolution, up to 2K)
- Nano Banana 2 isolates foreground elements on a pure white background
- The white result is edited to a black background (constrained edit preserving foreground exactly)
- A triangulation matte computes the true alpha channel:
alpha = 1 - (white - black) / 255 - The result is cropped back to original input dimensions
Parameters
| Parameter | Required | Description |
|---|---|---|
image |
Yes | Input image to remove background from |
prompt |
No | Describe what to isolate (e.g. “the car”, “the person”). If empty, all foreground elements are kept |
replicate_api_token |
Yes | Your Replicate API token — the model calls Nano Banana 2 internally |
Output
Always returns a PNG with alpha channel (RGBA) at the same dimensions as your input image.
Resolution
The model automatically selects the best output format (aspect ratio + resolution) to minimize padding. Images larger than 2K are scaled down and the result is scaled back up to original dimensions.
Billing
This model calls Nano Banana 2 twice per run (white + black background). You are billed for: - This model’s CPU compute time (minimal — just pixel math) - Two Nano Banana 2 runs (the main cost)
Your replicate_api_token is handled securely and never logged.