Image Runs in your browser

Image Contrast Adjuster

Adjust image contrast from -100 to +100. Pure Canvas API processing, 100% private, no uploads.

100% Private Works Offline Instant

or drag-drop, or paste · Double-click slider to reset · ↑↓ to nudge (Shift = ±10)

Privacy: all contrast adjustments run locally via the Canvas API. Auto-contrast, sigmoid, and histogram stretch computed in-browser.

About Image Contrast Adjuster

Adjust image contrast from -100 to +100. Pure Canvas API processing, 100% private, no uploads. Everything runs locally in your browser — your data never leaves your device.

How to use

Enter your input in the tool above.
Adjust any options to your preference.
Use the Copy or Download buttons to save the result.
Everything happens locally — your data never leaves your browser.

FAQ

Are my images uploaded?

No. Contrast adjustment runs locally via the Canvas API. Your images never leave your device.

What extras does this tool have?

Extras: (1) -100 to +100 range, (2) standard contrast formula, (3) live preview, (4) PNG/JPEG/WebP output, (5) quality slider, (6) accessible labels, (7) no upload, (8) fast, (9) keyboard-friendly, (10) drag-and-drop, (11) one-click apply, (12) preserves alpha, (13) lightweight.