| name | Watermark Remover |
| description | Remove visible Gemini AI watermarks from images using reverse alpha blending. Use when user mentions "remove watermark", "Gemini watermark", "去水印", or wants to clean AI-generated images. |
Watermark Remover
Instructions
This skill removes visible Gemini AI watermarks from images using mathematically accurate reverse alpha blending. It is based on GeminiWatermarkTool by Allen Kuo.
Important Notes
- This tool removes VISIBLE watermarks only (the semi-transparent logo in bottom-right corner)
- It does NOT remove SynthID invisible watermarks - those are embedded during image generation and cannot be separated from the image
- Best results on: slides, documents, UI screenshots, diagrams, logos, text-heavy images
- Always backup original images before processing
How It Works
Gemini adds watermarks using alpha blending:
watermarked = alpha × logo + (1 - alpha) × original
This tool reverses the equation:
original = (watermarked - alpha × logo) / (1 - alpha)
Watermark Size Detection
The tool automatically detects watermark size based on image dimensions:
| Image Size | Watermark | Position |
|---|
| W ≤ 1024 OR H ≤ 1024 | 48×48 | Bottom-right, 32px margin |
| W > 1024 AND H > 1024 | 96×96 | Bottom-right, 64px margin |
Usage
Remove watermark from a single image (in-place):
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove image.jpg
Remove watermark and save to new file:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove input.jpg output.jpg
Batch process a directory:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove ./input_folder/ ./output_folder/
Force specific watermark size:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove image.jpg --force-small
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove image.jpg --force-large
Verbose output:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove image.jpg -v
Show tool information:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py info
Supported Formats
- Input:
.jpg, .jpeg, .png, .webp, .bmp
- Output: Same as input format (preserves quality settings)
Examples
Example 1: Quick Watermark Removal
User request:
I have a Gemini-generated image with a watermark. Can you remove it?
You would:
- Ask for the image path
- Run the removal command:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove /path/to/image.jpg -v
- Confirm the watermark was removed
Example 2: Batch Processing
User request:
I have a folder of AI-generated images that all have watermarks. Can you clean them?
You would:
- Process the entire directory:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove ./gemini_images/ ./cleaned_images/ -v
- Report how many images were processed
Example 3: Preserve Original
User request:
Remove the watermark but keep my original file intact.
You would:
- Specify a different output path:
uv run .claude/skills/watermark-remover/scripts/watermark_remover.py remove original.png cleaned.png -v
Troubleshooting
"The image doesn't look different after processing"
The watermark is semi-transparent. If the original background was similar to the watermark color (white), the difference may be subtle. Try viewing at 100% zoom in the watermark area (bottom-right corner).
"Wrong watermark size detected"
Use --force-small or --force-large to manually specify the watermark size.
"Alpha map not found"
The skill requires alpha mask files in the assets/ directory. If missing, run:
python3 .claude/skills/watermark-remover/scripts/extract_masks.py /path/to/GeminiWatermarkTool/assets/embedded_assets.hpp
Credits
