How to remove the Gemini watermark
- Upload your image. Drag it into the box or click to pick a file. It loads instantly in your browser — nothing is sent anywhere.
- Auto mode does it instantly. The tool finds the star, confirms the match strength, and reverses the watermark blend automatically. Use the zoomed corner panels to check the result.
- Stubborn watermark? Switch to Brush mode. If your image is a screenshot, a JPEG, or a crop, the pixel-perfect math can't fully line up — switch to Brush, paint over the watermark, and it's reconstructed from the surrounding pixels. This works on any image.
- Download. Save the cleaned image as a lossless PNG.
For the cleanest result, use the original PNG straight from Gemini — that's when reverse alpha blending is pixel-perfect. Screenshots and re-saved JPEGs have shifted, recompressed pixels, so use Brush mode for those.
Why this tool keeps your images private
Most "free" online watermark removers upload your image to their server to process it. That means your picture sits on someone else's machine, and you're trusting their privacy policy. This tool is different: every step — loading, masking, the pixel rebuild, and the PNG export — runs locally in your browser using the Canvas API. Your image never touches a network. You can verify it yourself: open your browser's developer tools, go to the Network tab, and watch — there are no uploads while you work.
Where Gemini puts its watermark
Google's Gemini image model (nicknamed "Nano Banana") stamps a small, semi-transparent four-point star in the bottom-right corner of every image it generates. The exact size depends on the image resolution:
| Image size (longest side) | Star size | Margin from edges |
|---|---|---|
| Up to 1024px | 48 × 48px | 32px |
| Larger than 1024px | 96 × 96px | 64px |
The Auto-locate button uses these known measurements to mark the watermark region automatically based on your image's dimensions, with a little padding to catch the soft anti-aliased edge of the star.
How the removal works — reverse alpha blending
Gemini doesn't paint an opaque sticker on your image. It blends a semi-transparent white four-point star over the corner. Mathematically, every watermarked pixel is:
watermarked = α × 255 + (1 − α) × original
where α (alpha) is how opaque the star is at that pixel — known and fixed for every Gemini image. Because we know α and we know the star's colour is white (255), we can solve that equation backwards for the one unknown, the original pixel:
original = (watermarked − α × 255) / (1 − α)
That's reverse alpha blending. It doesn't blur, average, or guess — it recovers the exact pixels that were under the watermark. The star's per-pixel opacity (its "alpha map") was measured by capturing a Gemini watermark on a pure-black background, where the captured brightness directly equals the opacity. On a clean, uncropped Gemini image the restoration is pixel-perfect: the corner comes back exactly as it was before the watermark was added.
The only thing that degrades the result is editing the image after Gemini watermarked it — heavy re-compression, cropping, or resizing shifts the star and scrambles the alpha alignment. For those cases the manual panel lets you re-align the box or tweak the strength.
Gemini and Nano Banana
"Nano Banana" is the nickname for Google's Gemini image model — same model family, same white corner star, same alpha map. This tool removes the Nano Banana watermark exactly the same way it removes any Gemini watermark, automatically, with no extra steps.
Credits
The alpha-map measurements and Gemini size catalogue this tool builds on come from the open-source, MIT-licensed project GargantuaX/gemini-watermark-remover. Our implementation is a clean client-side port of the reverse alpha blending technique.
A note on responsible use
This is an image editor. Removing a visible watermark doesn't grant you rights you don't already have — make sure you own the image or have a licence to modify it before you remove anything, and follow the terms of whatever service generated it. The tool only removes the visible overlay; it doesn't alter any invisible provenance signal, and we don't suggest trying to.
Frequently asked questions
How do I remove the Gemini watermark from an image?
Just upload your image. The tool detects the Gemini star automatically from the image size, removes it with reverse alpha blending — the exact mathematical inverse of how Gemini stamped it — and gives you a clean PNG to download. No clicking, no brushing, no blur. Everything happens in your browser.
Is this Gemini watermark remover free?
Yes — completely free, no account, no sign-up, and no watermark on the output. There are no usage limits because all the processing runs on your own device, so there are no server costs to pass on.
Are my images uploaded to a server?
No. The tool runs 100% client-side in your browser using the Canvas API. Your image never leaves your device — you can confirm this by checking the Network tab in your browser's developer tools while you use it. This is the most private way to do it.
What is the Nano Banana watermark?
Nano Banana is the nickname for Google's Gemini image generation model. Images it produces carry the same small semi-transparent four-point star watermark in the bottom-right corner. This tool removes the Nano Banana watermark the same way it removes any Gemini watermark.
Where does Gemini put its watermark?
In the bottom-right corner. On images up to 1024px on the longest side, it's a 48×48px star set 32px in from the edges. On larger images, it's a 96×96px star set 64px in. The "Auto-locate" button targets exactly that region based on your image size.
Why is this better than tools that just blur the watermark?
Most free removers blur or "inpaint" the watermark area — they throw away the real pixels and paint a smudge over the corner. This tool does the opposite: because Gemini's star is a known semi-transparent white overlay, we mathematically reverse the blend and recover the actual original pixels underneath. On a clean Gemini image the result is pixel-perfect — the corner is restored, not smeared.
Will the image quality drop?
No. In Auto mode the watermark corner is mathematically restored to its original pixels rather than blurred, and output is a lossless PNG. If the image was screenshotted, recompressed as JPEG, cropped, or resized after Gemini added the watermark, the math can't line up perfectly — switch to Brush mode, which reconstructs the watermark area from the surrounding pixels and works on any image.
What image formats are supported?
JPG / JPEG, PNG, and WebP for input. Output is always a lossless PNG so you keep maximum quality and an clean alpha channel.
Does this remove the invisible SynthID watermark too?
No. This tool only removes the visible star overlay by reversing the alpha blend in that corner — it's an image editor that restores a small region of pixels. It does not touch invisible provenance signals, and we don't recommend trying to defeat those.
Can I use the cleaned images commercially?
That depends on Google's terms for the content you generated and your local laws — not on this tool. We just provide the image editor. Make sure you have the rights to use and modify the image before removing any watermark from it.