Image Contrast Adjuster
Drop in an image and download a higher- or lower-contrast version. Uses the standard contrast formula: each channel is pulled toward or away from 50% gray by the factor you set. Positive amounts pop the highlights and shadows; negative amounts mute the image toward gray. Output format matches the input where possible, defaulting to PNG. Conversion runs locally in your browser — files never leave your device.
Drop .png / .jpg / .jpeg / .webp / .bmp file here
or click to choose — or paste an image with ⌘V / Ctrl+V
Options
Privacy
Runs entirely in your browser — nothing is sent to any server.
Cost
Free. No sign-up, no watermark.
Supports
.png, .jpg, .jpeg, .webp, .bmp → .png
Related tools
Tools that work with the same formats — most users open one of these next.
Image Cropper
Crop any image (PNG, JPG, WebP, GIF, BMP, AVIF) right in your browser — drag a box, hit crop.
PNG Cropper
Crop PNG images in your browser — keeps transparency, lossless output, no upload.
Image to Grayscale
Convert any image to grayscale — pick the algorithm, runs entirely in your browser.
Image to Black & White
Convert an image to pure black & white using a threshold — runs in your browser.
Image to Sepia
Apply a classic sepia tone to any image — adjustable intensity, runs in your browser.
Invert Image Colors
Invert (negate) the colors of any image — runs entirely in your browser.
Frequently asked
Is Image Contrast Adjuster free to use?
Yes. Image Contrast Adjuster is completely free with no sign-up, no watermark, and no usage limits. Toolsly does not charge for any of its tools.
Do my files and data stay private?
Yes — Image Contrast Adjuster runs entirely in your browser using your device's CPU. Files and text are never uploaded to our servers, so your data stays private.
How does Image Contrast Adjuster work?
Open Image Contrast Adjuster, drop in your PNG, JPG, JPEG, WEBP, BMP file, choose any options, and click Convert. Your browser does the work locally and produces a PNG file you can save right away.
What's the maximum file size for Image Contrast Adjuster?
Because Image Contrast Adjuster runs in your browser, the maximum size depends on your device's available memory. Most modern phones and laptops handle files up to a few hundred MB without issues.