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Image Difference Checker

Highlight the pixels that differ between two similar images.

1

Input

2

Settings

3

Run

4

Results

Results will appear here once you run the tool.

About Image Difference Checker

Highlight the pixels that differ between two similar images. Drop one or more files into Image Difference Checker — it handles up to 2 at a time.

Your files stay on your device. ZyncTools has no upload step: the file is read in your browser, processed there, and handed straight back to you. There is no account, no watermark and no size cap beyond what your own device can hold.

Settings. Image Difference Checker gives you control over sensitivity, show differences as, highlight colour and fade the unchanged areas.

Also known as: diff, compare, difference, visual, regression.

How to use Image Difference Checker

  1. Add your input. Drop your files onto the upload area, or click to browse. You can add up to 2 at once, and they are read in your browser rather than uploaded.
  2. Choose your settings. Adjust sensitivity, show differences as, highlight colour and the other 1 settings to suit what you need.
  3. Run the tool. Press Run. Processing happens on your own device, so the time it takes depends on your machine rather than a queue.
  4. Save the result. Copy the output, or press Download to save it. Nothing is kept once you close the tab.

Frequently asked questions

Are my files uploaded when I use Image Difference Checker?

No. Image Difference Checker runs entirely inside your browser. Your file is read locally, processed on your own device, and handed straight back to you. You can confirm this yourself: open your browser's developer tools, watch the Network tab, and run the tool — no request carries your data anywhere.

Is Image Difference Checker free?

Yes, completely. No account, no sign-up, no watermark on your output, and no cap on how many times you can use it. The project is open source under the AGPL licence.

Is there a file size limit?

There is no server limit, because nothing is uploaded. The practical ceiling is your device's memory — on a modern laptop, files up to a few hundred megabytes are comfortable, while phones handle less. If a tab becomes unresponsive, the file was too large for the memory available.

Can I process several files at once with Image Difference Checker?

Yes — up to 2 at a time. When there are more than a few results they are packaged into a ZIP so you get everything in one download.

Does Image Difference Checker work offline?

Mostly. The site caches itself after your first visit, so it keeps working without a connection. Tools that need a specialised library — PDF editing, OCR, QR codes, MP3 encoding — need a connection the first time you run them, then that library is cached too.

Related image tools

Image Compressor Shrink image file size with a quality slider or a target file size. Image Resizer Resize images by pixels, percentage or to fit inside a box. Image Format Converter Convert between PNG, JPEG, WebP, AVIF, BMP, HEIC and SVG raster output. Image Cropper Crop to an aspect ratio, exact pixels, or a centred square. Rotate & Flip Image Rotate by any angle and mirror images horizontally or vertically. Image Filters & Adjustments Adjust brightness, contrast, saturation, blur and apply photo presets.