brightness · contrast · live · local

Adjust brightness & contrast with live preview

Drag the sliders and watch the image update in real time. Brightness shifts the midline; contrast stretches the dynamic range. Outputs a lossless PNG.

Brightness & Contrast
Source
—
no file
Output
—
PNG
Brightness
0
/100
Contrast
0
/100
Brightness:0
Contrast:0
input · image

image/* · runs locally · nothing uploaded

output · preview
Original
—
Adjusted
—
Quick Start

How it works

Pick an image, tune the options, then download the result. Everything runs in your browser.

  1. 01

    Pick an image

    Drop in a PNG, JPG, or WebP. The image is loaded into a hidden canvas.

    Files stay in memory as an HTMLImageElement — the original bytes are never uploaded, and EXIF metadata is preserved until you explicitly transform it.

    uploadcanvaslocaldecode
    input · bytesimage · loaded
    file.png
    loaded · decodedcanvas · ready
  2. 02

    Tune brightness

    Brightness shifts every channel by ±100 — the simplest exposure fix.

    Encoder quality is exposed where the format supports it — JPEG and WebP get a 0–1 quality slider; PNG is lossless. Options re-render the canvas immediately.

    brightoptionslive previewencoderquality
    B · tunable0 · live
    v + 0
    options applied · liveencoder · live
  3. 03

    Tune contrast

    Contrast stretches values around the midpoint — boosts pop or flattens.

    Pixel work runs on the Canvas 2D context — drawImage resamples with the browser’s bilinear filter and getImageData/putImageData back per-pixel passes.

    contrastrenderCanvas 2Dpreviewpx-perfect
    C · resampled0 · px-perfect
    cf * (v-128) + 128
    preview · livepx-perfect
  4. 04

    Download PNG

    Save the result. Output is lossless PNG.

    Downloads ship via a hidden anchor with an object URL — no server round-trip, and the file on disk is untouched. The output filename inherits a sensible suffix.

    exportdownloadblobclient-sideobject URL
    ok · blobready · saved
    file-bc.png
    shipped · ready to shipsuccess
Pro tips

Browser-only image work that scales

Convert with quality control

JPEG/WebP let you pick a 0–1 quality. Default 0.92 is a good compromise of size and visible quality.

PNG isn’t free

Use PNG only for transparency or sharp edges. For photos, WebP is smaller at the same perceived quality.

Strip EXIF for privacy

Photo EXIF often contains GPS, camera model, and timestamps. Strip before sharing public uploads.

Watch the colour profile

Convert to sRGB before web export. Wide-gamut images render oversaturated in non-managed browsers.

AVIF when it’s available

AVIF beats WebP on size at the same quality. Detect support via <picture> with fallbacks.

Lazy-load below the fold

Add loading="lazy" on <img>. The browser handles scheduling — no IntersectionObserver needed.

Use Cases

When to use this tool

Common workflows it speeds up.

Lift dark photos

Recover detail from underexposed phone snaps. Decoded into a Canvas 2D context — original bytes never leave the tab, so you can process customer-uploaded photos, internal screenshots, or sensitive diagrams without privacy concerns.

px-perfect

Pop product shots

Crank contrast for catalogue images. Encoders expose quality 0–1 where the format supports it (JPEG, WebP); PNG and AVIF stay perceptually lossless. Pick 0.85 for web, 0.95 for archival, 0.7 for thumbnails.

quality-tunable

Scan cleanup

Boost contrast on washed-out scans. Pair with the EXIF Stripper before sharing user-uploaded photos publicly. Camera serial numbers, GPS coordinates, and timestamps often hide in image metadata and leak more than the picture itself.

format-aware

UI screenshots

Even out screenshot exposure for docs. Output preserves colour profile (sRGB) so it renders consistently across browsers, monitors, and print pipelines. Wide-gamut workflows can opt into Display P3 for modern Apple devices.

EXIF-safe

Quick fixes

No full editor required for a touch-up. Re-runs only on option changes, never on window resize, so the canvas stays responsive on large images. drawImage uses the browser's bilinear filter for fast resampling.

client-side

Social ready

Brighten before posting under low light. Downloads as .png, .jpg, .webp, or .avif with the correct MIME so editors apply native handling on save. The filename inherits a sensible suffix derived from the input.

compression-ready
FAQ

Frequently asked questions

Yes — it&apos;s the classic GIMP-style brightness/contrast formula scaled to ±100.
Extreme settings can clip. Stay within ±50 for natural-looking results.
Yes — only RGB is touched. Alpha is passed through unchanged.
No. The adjustment runs locally in your browser — your image never leaves the device.
Lossless PNG so you can re-edit without generational loss.
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