Gemini sparkle remover
Remove the Gemini watermark sparkle
Google's Gemini and Nano Banana burn a small visible sparkle into the corner of the images they make. This finds it and removes it by reverse alpha-blending, inverting the exact equation Google used to blend it in. That means no generative fill and no hallucinated pixels, just the original pixels recovered by math.
Runs entirely in your browser. Your image is never uploaded or stored.
Why a remover is a forensics tool
A visible watermark tells you an image is AI. A remover shows you how little its absence is worth. The sparkle is blended into a handful of corner pixels, and because that blend is exactly reversible it lifts off in one click with no trace left behind. So an image with no visible sparkle is not an image that was never AI: it is just as easily one where the mark was removed, cropped out, or never shown in the first place (Gemini already omits it for Ultra, AI Studio and API output). Once you have taken one off, you stop reading a missing visible mark as proof of a real photo, and you look instead at what survives removal, like the invisible SynthID watermark and C2PA provenance metadata.
How it works
Gemini adds the sparkle by alpha-blending a white glyph over the image:
watermarked = alpha·white + (1 − alpha)·original. Because the glyph's opacity map
(alpha) is known, the blend is exactly reversible:
original = (watermarked − alpha·255) / (1 − alpha). The tool locates the sparkle in the
corner positions Gemini uses, then applies that inverse pixel by pixel. Nothing outside the sparkle's
footprint is touched.
What it does and doesn't do
| Point | Detail |
|---|---|
| Removes | The visible corner sparkle from Gemini / Nano Banana output, at its original resolution. |
| Does not remove | The invisible SynthID watermark, or C2PA "made with AI" metadata. The sparkle is only the visible mark. |
| Needs | The sparkle present in a known corner position. A cropped, resized or re-rendered image where the sparkle has moved may not be found. |
Sources
- Kuo, A. (allenk). GeminiWatermarkTool — the reverse alpha-blending removal + Snap Engine detector ported here (MIT). github.com/allenk/GeminiWatermarkTool