Grayscale Image Converter
Upload a photo or design, choose a grayscale method, preview the black-and-white result, and download PNG or JPG.
Your grayscale image will appear here
Convert color images to grayscale
Three grayscale methods
Use luminance for natural photos, average for simple tone, or lightness for balanced extremes.
Instant preview
Compare the selected black-and-white conversion before downloading.
Private local processing
您的圖像保留在您的瀏覽器中。 ImageConver 不上傳原始檔。
它是如何運作的
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1
上傳圖片
Choose a color image from your device.
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2
Pick a method
Select luminance, average, or lightness grayscale conversion.
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3
下載
Save the converted image as PNG or JPG.
Choosing a grayscale method
Luminance weighting usually looks best for photographs because it follows how human vision sees red, green, and blue brightness. Average grayscale treats all channels equally. Lightness uses the midpoint between the darkest and brightest channels, which can help graphic images with strong colors.
常見問題
Which grayscale method should I use?
Luminance is the best default for most photos. Average and lightness can be useful for graphics or stylized images.
Does grayscale conversion remove transparency?
No. Alpha transparency is preserved when the output format supports it.
我的圖片上傳了嗎？
No. Your image stays in your browser and grayscale conversion runs locally.
Grayscale Image Converter last reviewed: Jun 24, 2026.