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Image Comparator

Compare two images in your browser, highlight pixel differences, and tune tolerance to ignore compression noise. No uploads leave your device.

Upload a reference and a comparison image to get a magenta diff overlay and a quantified match rate. All processing stays on-device for privacy.

1. Upload reference image

Choose reference image

2. Upload comparison image

Choose comparison image

3. Matching sensitivity

Tolerance: 0%

Strict (0) Loose (100)

Tolerance: 0%

JPEG compression can introduce tiny pixel shifts. Raise the tolerance to ignore acceptable noise; keep it at 0% for byte-level verification.

Result

Waiting for two images

Match rate
–
Diff pixels
–
Total pixels
–
Magenta pixels = differences
Gray pixels = matching areas (reference preview)

Diff preview

Upload two images to start

Use cases

UI regression checks

Compare before/after screenshots to catch unintended visual changes before release.

Asset QA

Verify exported banners or thumbnails still match the approved source after compression or resizing.

Compliance & evidence

Share a quantified match rate for reviews or audits without sending files to external services.

Pro tips

  • Keep reference and comparison oriented the same. The tool rescales dimensions, but large aspect ratio shifts will surface many differences.
  • Stay on the tab when processing very large images so the browser doesn’t throttle the calculation.
  • Fully transparent pixels are ignored. Add a solid background if you need to compare transparent edges precisely.

How to use

  1. 1

    Add the reference image

    Upload the baseline or golden image that you want to trust as the source of truth.

  2. 2

    Add the comparison image

    Upload the screenshot or export to verify. Different dimensions are automatically scaled to the reference.

  3. 3

    Adjust tolerance and read the diff

    Move the tolerance slider to ignore compression noise. Review the magenta overlay and the reported match percentage.

Frequently Asked Questions

Are my images uploaded to a server?
No. All processing happens directly in your browser. Files never leave your device, and nothing is stored on any server.
What image formats are supported?
Any format your browser can open: JPEG, PNG, WebP, GIF, BMP, SVG, AVIF, and more. The diff is drawn on a canvas for quick inspection.
How are transparency and alpha handled?
Pixels that are fully transparent in both images are treated as matching, regardless of their RGB values. Otherwise, alpha differences are counted in the diff.
How should I pick a tolerance value?
Use 0% for cryptographic checks, 1–5% for compressed exports, and higher values when comparing screenshots with anti-aliasing or font rendering differences.