Compare two images

Spot the difference between two versions of an image, such as an original and a compressed copy. Swipe between them, view them side by side, or see every changed pixel highlighted.

First image

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JPG, PNG, WebP, GIF, AVIF or BMP, up to 80 MB.

Second image

Drop an image hereAdd an image

JPG, PNG, WebP, GIF, AVIF or BMP, up to 80 MB.

Compared on your device. Your images are never uploaded.

How it works

  1. Your browser decodes both images and lines them up at the same size.
  2. It compares every pixel and counts those that differ by more than the sensitivity you set.
  3. It measures overall similarity as PSNR, a standard score for image quality, and draws the differences in red.

Supported formats

Opens
JPG, PNG, WebP, AVIF, BMP and GIF (the first frame of an animation), two at a time
Saves
Nothing, except the difference map as PNG if you want it.
Limits
Two files up to 80 MB each.
  • Images of different sizes are compared by scaling the second to the first.
  • Large images are compared at up to 2048 pixels on the long side, which shows any difference you could see by eye.

Your image stays on your device

This tool runs entirely in your browser. The image is never uploaded, so there is nothing for us to store, see or delete.

To check, open your browser’s developer tools, switch to the Network tab and use the tool: you will not see your image being sent anywhere.

Questions

Are my images uploaded anywhere?

No. The image is read and processed by your own browser. Nothing is sent to our servers, so there is no copy of your image anywhere but your own device.

What does PSNR mean?

Peak signal-to-noise ratio: a standard measure of how close two images are. Above about 40 dB, most people can’t see a difference; below 30 dB, differences are easy to spot.

Why are there tiny differences everywhere?

Re-saving a JPG or WebP changes pixels slightly, even when it looks the same. Raise the Sensitivity to ignore that and show only real changes.