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Compare Two Images

Spot every pixel that changed between two versions.

  • Free
  • No signup
  • Nothing uploaded
  • No watermark

Original

Drop a file here

Image · read on your device, never uploaded

Changed version

Drop a file here

Image · read on your device, never uploaded

Sensitivity

8

How different two pixels must be to count as a change. Raise it to ignore anti-aliasing and compression noise.

Both files are rendered and compared on your device. Neither is uploaded.

How to Compare Two Images and Spot Changes

Compare Two Images: before and after PNG A BEFORE COMPARE TWOIMAGES PNG A AFTER

Two screenshots of a web page, two versions of a logo, or a product photo before and after retouching can look identical at a glance while hiding small edits. This tool lines the images up and checks them pixel by pixel, then shows you exactly where they differ.

Drop the original and the changed image, set how sensitive the check should be and press Compare visually. You get the percentage of pixels that changed and four ways to look at the result: a slider, a highlighted difference map, a see-through overlay and side by side.

No software to install Free Works on any device

Steps to Find Differences in Images

  1. 1. Add both images

    Put the earlier picture in Original and the newer one in Changed version. PNG, JPG and WebP all work.

  2. 2. Set the sensitivity

    The Sensitivity slider decides how different two pixels must be to count. Raise it to ignore JPEG noise and soft edges; lower it to catch the faintest change.

  3. 3. Press Compare visually

    The images are drawn and compared in the page. A summary gives the number and share of pixels that differ.

  4. 4. Choose a view

    Slider sweeps between the two, Differences highlights changed pixels, Overlay blends them, and Side by side shows both in full.

  5. 5. Download the difference map

    Save the highlighted map as a PNG to attach to a bug report or share with a designer.

No .png file to hand? Download a sample Image file (253.4 KB) and try it.

Try it now

What Is Visual Image Comparison?

Visual comparison checks the colour of each pixel in one image against the pixel in the same place in the other. Any pixel whose colour moved further than the sensitivity allows is marked as changed. Designers and testers call this visual regression testing when it is used to catch unexpected changes in a website or app.

Why Compare Files Side by Side?

Reading two versions by eye is slow, and small changes slip past even careful readers. A comparison puts both copies next to each other and marks every added, removed and changed line, cell or word, so nothing gets missed.

“The change you do not notice is the one that causes trouble later.”
  • Every change marked in colour
  • Catch edits before you sign
  • Check data after an import
  • Both files stay on your device
  • No more reading line by line
  • Spot quiet changes in contracts
  • Review code before it goes live
  • Proof that nothing else changed

Popular Uses for File Comparison Tools

People reach for a comparison whenever two copies of something might not match.

  • Contract revisions See exactly which clauses the other side changed before you agree to the new draft.
  • Spreadsheet checks Find the cells that changed between last month’s price list and this month’s.
  • Thesis drafts Compare your latest chapter with the version your guide marked up last week.
  • Code reviews Look at two versions of a script or stylesheet and see each line that moved.
  • Database schemas Check two CREATE TABLE statements or schema dumps before running a migration on live data.
  • Design proofs Place two images together to spot a moved logo or a changed colour.
  • Config files Compare JSON, YAML or INI settings between a working server and a broken one.
  • Policy updates See what really changed in a revised policy PDF instead of trusting the summary.

What the Image Compare Tool Offers

Before and after slider

Drag across the image to reveal the original on one side and the new version on the other.

Difference map

Changed pixels light up clearly, so a moved button or a retouched blemish is easy to find.

Overlay and side by side

Blend the two images or place them next to each other, whichever makes the change clearer.

Adjustable sensitivity

Tune the threshold from strict to relaxed to cut out compression artefacts.

Measured change

Reports both the count of changed pixels and the share of the whole image.

Why Use ToolXkit for Compare Two Images?

Your files stay with you

Everything runs inside your browser. Nothing you open or type is uploaded to a server.

Comparison Tools for Different Users

Lawyers and legal staff

Check each new draft of an agreement against the one already approved.

Students

Compare an edited essay with the original to learn from every correction made.

Developers

Review changes in code, config and SQL without setting up a separate diff program.

Accountants

Match two versions of a ledger or price sheet and find the stray figures.

Editors and writers

See what a co-author or client changed in a manuscript between two rounds.

HR teams

Confirm that an updated contract or handbook differs only where it was meant to.

Best Times to Compare Two Files

A side-by-side comparison helps when you are:

  • Reviewing a returned contract
  • Checking a reissued price list
  • Preparing code for release
  • Planning a database migration
  • Hunting a settings mismatch
  • Reading a co-author’s edits
  • Sorting out two saved copies
  • Checking a revised design proof

Tips for Image Comparison

  1. Compare images of the same size. Different dimensions are placed on one larger canvas without resizing, so the extra area counts as changed.

  2. Use PNG screenshots where you can. JPEG compression adds tiny colour shifts that need a higher sensitivity to ignore.

  3. If everything seems to differ, raise the sensitivity a little at a time until only the real edits remain.

  4. Take both screenshots at the same browser zoom and window width, or the layout itself will shift.

Frequently Asked Questions

Answers to common questions about this tool.

How can I find the difference between two pictures?

Add both images here and press Compare visually. The Differences view highlights every pixel that changed, and the slider lets you sweep between the two to see each edit in context.

Can it compare images of different sizes?

It will, by placing both on a canvas the size of the larger one, but it does not scale them. A resized copy of the same photo will show as mostly different, so resize one to match first.

What does the sensitivity setting do?

It sets how far a pixel’s colour must move before it counts as changed. At 0 even invisible shifts are flagged. Higher values ignore anti-aliasing and compression noise and report only visible edits.

Are my images uploaded?

No. Both pictures are decoded and compared by your browser, on your device. That makes it safe for unreleased designs, private photos and screenshots of internal systems.

Can I compare two PDF pages visually?

This page is for image files. For documents, use the visual PDF comparison tool, which renders each page and compares them in the same way.

Is Compare Two Images free, and do I need an account?

Yes. It costs nothing, and there is nothing to sign up for. Open the page, add your two files or paste two blocks of text, and the differences appear. There is no trial period and no limit on how often you compare.

Can I compare two different formats, like a PDF and a Word file?

Each compare tool is built for one kind of file, such as PDF, Excel, JSON or plain text. To compare across formats, convert one of them first, or copy the text of both into Compare Text.

How big can the files be?

There is no fixed cap. Everything runs in your browser, so very large files depend on how much memory your device has. A laptop handles bigger files than an older phone, and closing other tabs can help.

Will Compare Two Images show formatting changes as well as text?

It depends on the tool. Most compare tools focus on content, such as words, lines, cells or values, because that is where meaningful changes hide. Compare PDF Visually is the one to use when the look of the page matters.

Further reading

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