How to compare two images
- Choose the first and second image.
- Use Slider to drag between them, Side by side to view both, or Blend to fade one over the other.
- Open Differences to see changed pixels in pink, and read the percentage of pixels that differ.
- Adjust the threshold to ignore tiny changes, then download the difference image if you need it.
Useful for checking a design against a screenshot, an edit against the original, or how much a compressed copy differs from the source.
Questions
Are my images uploaded?
No. Both pictures are compared by your browser on your own device. Nothing is sent anywhere.
What if the two images are different sizes?
The second image is matched to the size of the first, either by stretching it to fill or by fitting it inside with white borders. A note shows both sizes. For a fair pixel comparison, use two pictures of the same size when you can.
How does the difference view decide a pixel changed?
For each pixel it finds the biggest change in red, green, or blue between the two images. If that change is above the threshold (0 to 255), the pixel counts as changed. The percentage is changed pixels divided by all pixels.
Why do two images that look the same show differences?
JPG compression, resizing, and color profile changes alter pixel values slightly. Raise the threshold to ignore small noise and keep only visible changes.
Large pictures look slightly softer. Why?
For speed, the comparison works on a version of up to 2400 pixels on the long side. Your original files are not changed.
Credits
Built by OneTooling using standard browser features. No third-party code runs on your data.