Upload an image to threshold
Accepted formats: JPG, PNG, WEBP, BMP, GIF (non-animated)
Paste (Ctrl/⌘+V) or drop an image — or import from a URL
Thresholding reduces an image to just two tones: every pixel is compared against a single brightness cutoff, and pixels above it become one color while pixels below it become another. There are no grays or gradients in between, which makes it ideal for extracting clean line art, sharpening up a scanned document or signature, creating bold silhouettes, or preparing a stencil for screen printing, vinyl cutting, or laser engraving. Image Machine measures each pixel's luminance, so the split follows perceived brightness rather than a single channel, and lets you drag the cutoff to decide how much of the image falls on each side. By default it produces classic black-on-white, but you can pick any two colors for a high-contrast duotone, and a single click swaps which side is light or dark. Everything runs locally in your browser on the HTML canvas — your image is never uploaded, transparency is preserved, and there's no sign-up, no watermark, and no quality loss.
How It Works
Choose a tool
Pick from 120+ tools to resize, convert, compress, or enhance your image.
Upload & edit
Drag and drop your image and adjust the settings. It stays on your device.
Download
Save your result instantly — no watermark, no sign-up required.
Why Image Machine?
Your files never leave your device
All processing runs locally in your browser. Your images are never uploaded to a server.
Completely free
Every tool is free, with no limits, no watermarks, and no hidden costs.
Lightning fast
No upload waiting — your images are processed instantly on your own device.
Professional quality
Pixel-perfect output with full control over format, size, and quality.
Frequently Asked Questions
What does the threshold tool do?
It converts your image to a hard two-tone result. Each pixel's brightness is compared to the cutoff you set: brighter pixels are painted the light color and darker pixels the dark color, with nothing in between. The effect is the classic 1-bit, high-contrast black-and-white look used for line art, logos, and clean scans.
How is threshold different from grayscale, posterize, or dithering?
Grayscale keeps every shade of gray — it only removes color. Posterize reduces each color channel to a few levels but still keeps multiple tones and the original hues. Dithering can also cut an image down to two colors, but instead of a hard split it scatters a dot or noise pattern to fake the in-between shades, so it looks grainy rather than crisp. Threshold is the hardest reduction of all: a single brightness cutoff splits the image into exactly two flat colors with crisp edges and no pattern.
Can I use colors other than black and white?
Yes. Both the dark and light colors are adjustable, so instead of black-on-white you can make a high-contrast duotone — for example cream on navy, or any two brand colors. The Invert button swaps which side of the cutoff gets the light versus the dark color.
Is my image uploaded, and does it keep transparency?
No upload — thresholding runs entirely in your browser using the HTML canvas, so your image never leaves your device, and it works offline once the page has loaded. Only the red, green, and blue channels are changed; the alpha channel is left untouched, so transparent areas of a PNG stay transparent. There's no sign-up, no watermark, and no quality loss.