Gemini Watermark Remover

Remove the visible Gemini AI watermark (star/sparkle logo) from generated images using mathematically accurate reverse alpha blending. Fast, offline, single binary with zero runtime dependencies.

When to Use

• Remove the Gemini watermark from AI-generated images
• Batch process a directory of Gemini-generated images
• Clean images before publishing or sharing
• Automate watermark removal in pipelines

Quick Start

Install

Option 1 — Recommended: Build from source (Rust toolchain required)

cargo install gemini-watermark-removal
gemini-watermark --version

Building from source lets you audit the code before running it and avoids dependency on a third-party pre-built binary.

Option 2 — Pre-built binary (third-party download)

Security notice: The installer downloads a binary from the easynote-cc GitHub organization, which is an independent third party. Review the source at https://github.com/easynote-cc/gemini-watermark-removal before proceeding. SHA256 verification is mandatory; the install will abort if the checksum file is missing.

# Interactive (asks for confirmation before downloading)
./scripts/install.sh

# Non-interactive (auto-confirm, e.g. in a script)
./scripts/install.sh --yes

# Install a specific pinned version
VERSION=v0.1.1 ./scripts/install.sh

Supported platforms: macOS (Apple Silicon / Intel), Linux (x86_64 / ARM64), Windows (x86_64, via Git Bash / MSYS2).

Basic Usage

# Single image (auto-detect watermark, save as photo_cleaned.jpg)
./scripts/gemini-watermark photo.jpg

# Specify output path
./scripts/gemini-watermark photo.jpg -o clean_photo.jpg

# Batch process directory
./scripts/gemini-watermark ./input_dir -o ./output_dir

# Force removal without detection
./scripts/gemini-watermark photo.jpg -o clean.jpg --force

How It Works

Gemini adds a semi-transparent white star/sparkle logo to generated images using alpha blending:

watermarked = alpha * 255 + (1 - alpha) * original

This tool reverses the equation to recover the original pixels:

original = (watermarked - alpha * 255) / (1 - alpha)

The alpha maps (watermark transparency patterns) are embedded in the binary at two sizes:

• 48x48 with 32px margin: for images where either dimension <= 1024px
• 96x96 with 64px margin: for images where both dimensions > 1024px

Detection

Before removal, a three-stage detection algorithm checks if a watermark is present:

1. Spatial NCC (50% weight): normalized cross-correlation with the alpha map
2. Gradient NCC (30% weight): edge signature matching via Sobel operators
3. Variance Analysis (20% weight): texture dampening detection

Images without detected watermarks are automatically skipped to protect originals.

CLI Parameters

Parameter	Short	Default	Description
input		(required)	Input image file or directory
--output	-o	{name}_cleaned.{ext}	Output file or directory
--force	-f	false	Skip detection, process unconditionally
--threshold	-t	0.25	Detection confidence threshold (0.0-1.0)
--force-small		false	Force 48x48 watermark size
--force-large		false	Force 96x96 watermark size
--verbose	-v	false	Enable detailed output
--quiet	-q	false	Suppress all non-error output

Supported Formats

Format	Read	Write
JPEG (.jpg, .jpeg)	Yes	Yes (quality 100)
PNG (.png)	Yes	Yes
WebP (.webp)	Yes	Yes
BMP (.bmp)	Yes	Yes

Usage Examples

# Remove watermark with verbose output
./scripts/gemini-watermark photo.png -o clean.png -v

# Lower detection threshold (more sensitive)
./scripts/gemini-watermark photo.jpg -t 0.15

# Force large watermark size regardless of image dimensions
./scripts/gemini-watermark photo.jpg --force-large -o clean.jpg

# Batch process, quiet mode
./scripts/gemini-watermark ./gemini_images/ -o ./cleaned/ -q

# Force removal on all images in batch (no detection)
./scripts/gemini-watermark ./images/ -o ./output/ --force

Output

• Single file: Saves to specified -o path, or {name}_cleaned.{ext} by default
• Directory: Saves all processed images to the output directory with original filenames
• Skipped images: Images without detected watermarks are not processed (unless --force)
• Exit code: 0 on success, 1 if any image fails

Troubleshooting

Download failed or checksum missing during install

If the SHA256 checksum file is absent for a release, the installer will abort to protect you from an unverified binary. Build from source instead:

cargo install gemini-watermark-removal

Unsupported platform

cargo install works on any platform with a Rust toolchain. The pre-built binary installer covers macOS, Linux, and Windows (Git Bash / MSYS2) only.

"No watermark detected" on a watermarked image

• Try lowering the threshold: -t 0.1
• Or use --force to skip detection

Image looks distorted after removal

• The image may not have a Gemini watermark. Use detection (don't use --force)
• Try --force-small or --force-large to match the correct watermark size

"Image too small" warning

The image dimensions are smaller than the watermark region. This typically means the image does not have a Gemini watermark.

Limitations

• Visible watermark only: This tool removes the visible star/sparkle logo watermark
• Cannot remove SynthID: Google's invisible watermark (SynthID) is embedded at the pixel level during generation and cannot be reversed
• Fixed positions only: Only handles watermarks in the standard bottom-right position