Black & White Image Converter turns color images into grayscale locally in your browser, with batch processing and downloads for printing, ID photos, and design asset cleanup.
Key Features
- Upload JPG, PNG, GIF, BMP, WebP, and SVG (supports folder import)
- Convert to grayscale while keeping the original resolution
- Side-by-side preview, single download, and ZIP download
How To Use
- Click “Choose images” or drag files into the upload area
- Select an item in the list to preview
- Use “Process current” or “Process all” to generate results
- Download the current result, or download all results as a ZIP
Tips
- Grayscale conversion uses a weighted luminance formula
- Drag and drop or import a whole folder for quick batching
- Output is always JPG; transparent pixels are filled with white
Formula
Grayscale is computed with the luminance formula: 0.299 × R + 0.587 × G + 0.114 × B, then written back to RGB channels.
FAQ
Why is the output always JPG?
JPG is widely compatible for printing, sharing, and further editing, which helps avoid format-specific issues.
What happens to transparent backgrounds?
JPG does not support transparency, so transparent pixels are filled with a white background.
How does batch download work?
Batch download packages generated results into a ZIP file.
Will it change image dimensions?
No. It only changes color channels and keeps the original resolution.
Privacy
All processing runs locally in your browser. Images are not uploaded to a server.