Images · Local utility

Image Diff

Compare two PNG, JPEG, or WebP images pixel by pixel with split, slider, fade, highlight, and mask views.

Runs locally · Nothing is uploaded

Content maintained by Toolars · Updated 2026-09-03

Image diff · local pixels

Image Diff

Compare two PNG, JPEG, or WebP images pixel by pixel in an isolated Worker with split, slider, fade, highlight, and mask views.

Ready

Original

Choose original image

Changed

Choose changed image

View

Match threshold: 0.10Ignore antialiased edges

Choose two images to compare

Ready

How Image Diff works, privacy, and related tools

Task path / input to outcome

How to compare two images

01
Choose the two images
Pick the Original and the Changed image — PNG, JPEG, or WebP, up to 12 MiB each, 8,192 pixels per side, and 8 million pixels for the precise comparison. JPEG files are normalized to their EXIF orientation on load, both sides show their format, dimensions, and file size, and Swap sides exchanges them in one click.
02
Read the verdict
Matching dimensions compare automatically in an isolated Worker. Zero differing pixels at threshold 0 reports Pixel-identical; zero differences at a higher threshold says exactly that — No differences above the current threshold — and anything else names the differing pixel count and its share of all compared pixels.
03
Switch between the five views
Split shows both images side by side with synchronized zoom and pan — scroll to zoom, drag to pan, and the buttons or arrow keys work without a mouse. Slider reveals the change through a keyboard-operable divider, Fade overlays one image on the other at adjustable opacity, Highlight marks the differing pixels over the original, and Difference mask shows them alone.
04
Tune the threshold and antialiasing
The match threshold sets how far apart two colors may be before counting as different: 0 is exact, and higher values absorb JPEG re-compression noise. Ignore antialiased edges skips the soft boundary pixels of rendered text and shapes; every change re-compares automatically with the previous run cancelled.
05
Export the mask
Export mask PNG saves a transparent-background mask with every differing pixel marked, ready for a ticket or review. Pixel-identical means the decoded pixels match, not that the files are byte-identical — different encoders and metadata produce equal pixels from different bytes, so verify file hashes with Hash Checker when that matters.

Tool facts

Processing: In your browser
Input leaves this device: Never
Retention: Nothing is stored
Price: Free

Your input stays in the browser.

Image Diff uses its verified local execution path and does not create a hidden input or output history.

Local execution

Runs inside the current browser tab.

No hidden processing

Active tool data never becomes a Toolars document record.

No account required

Use the core workflow without creating a profile. Favorites sync to your account after you sign in.

Immediate reset

Clear the tab and the active working data is gone.

When Image Diff is useful

Focused transformations

Complete one well-defined browser task without setting up another application.

Copy-ready output

Review the result beside its source before copying or downloading it.

Fast validation

Catch malformed input and stale results before they enter another workflow.

What Image Diff actually does

A design revision came back and someone must confirm only the intended region changed; a UI regression suite has screenshots from two builds and the failing area hides somewhere in a long page; two exports from the same pipeline should be identical but the eye cannot prove it. Load both images — the comparison runs locally — and switch to Highlight to see the stray watermark glow red over the original, drag the Slider where a button shifted by two pixels, and export the mask to attach to the bug. When the screenshots have different dimensions, the workspace says Visual comparison only instead of inventing numbers, and the resize step stays with Image Resizer.

Result stays explicit

The current result and selected settings stay visible before copy or download.

Built for review

Inspect relevant structure, metadata, or source context before using the result.

Private by default

No active workspace value is stored or sent to a server.

Errors stay explicit

Invalid values return a clear error instead of stale output.

Common questions

Which image formats are supported?

PNG, JPEG, and WebP, verified by file signature rather than file name, up to 12 MiB each. GIF animations, HEIC, SVG, and PDF pages are deliberately out of scope: they need either animation handling or decoders that vary across browsers, which would make the pixel verdicts unreliable.

What happens when the images have different dimensions?

The workspace switches to Visual comparison only: Split, Slider, and Fade keep working so you can inspect both versions, but no pixel counts or percentages are reported, because a number computed against rescaled pixels would be a false verdict. Resize one side with Image Resizer first when you need the precise comparison.

What does the threshold change?

It is the color distance two pixels may have before counting as different. Threshold 0 counts every channel difference, which strict export checks want but which flags JPEG re-compression noise; raising it absorbs that noise. Ignore antialiased edges additionally skips the soft boundary pixels that rendering produces, which keeps text and shape edges from flooding the count.

Does pixel-identical mean the files are identical?

No. The verdict compares decoded pixels after EXIF normalization: two files with different encoders, compression levels, or metadata can decode to identical pixels. When the bytes themselves matter — integrity checks, cache keys — use Hash Checker on the files.

Are colors compared exactly?

Colors are compared as the browser decodes them into RGBA, without color-management transforms, so the comparison is exact in that decoded space rather than a print-proof color measurement. Transparency participates through the alpha channel, and where browsers decode differently the honest scope is the pixels this browser saw.

Are my images uploaded anywhere?

No. Both files stay in the current browser tab, decoding and the pixel comparison run in an isolated local Worker, nothing is sent or retained, and no account is required.

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