Image Resizer
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Resize images to any width and height. Lock aspect ratio, choose presets, and download instantly. 100% browser-based.
Grayscale Converter
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Convert color images to grayscale or black and white. Choose between luminosity, average, lightness, and threshold modes.
Grayscale Converter
Drop an image here, or click to browse
PNG, JPG, WebP, GIF up to ~20 MB
About This Tool
Four Grayscale Methods
- Luminosity (default) – perceptually accurate; uses 0.299R + 0.587G + 0.114B.
- Average – simple (R+G+B)/3; tends to look flatter than Luminosity.
- Lightness – (max+min)/2; preserves more contrast.
- Threshold (B&W) – pure black or white based on a brightness cutoff.
When to Use Each
For photographs, Luminosity almost always looks best. Threshold is for stylized, posterized, or scanned-document looks. Try each on your image.
Frequently Asked Questions
Why does my photo look flat after converting?
Try the Lightness method instead of Average for more contrast, or use a brightness/contrast tool afterwards. Luminosity is the most natural-looking for portraits and landscapes.
What is a good threshold value?
128 is a neutral mid-gray cutoff and works for most images. Lower values (around 80-100) keep more dark areas; higher values (160+) keep more bright areas. Try several to find the best look.
Will this work on PNGs with transparency?
Yes - transparent pixels stay transparent. Only the visible color information is converted. Save as PNG or WebP to preserve the alpha channel.