Compare images (before and after)
Compare two images with a before-and-after slider, an overlay, or the differences highlighted in red.
Before and after.
Available in: 
Compare images (before and after): what it is for
This tool compares two images in three ways: a before-and-after slider, an overlay with adjustable transparency, and differences mode, which paints every changed pixel red and shows the percentage that changed.
Download the comparison on screen as an image. The images are never uploaded to a server: everything happens in your browser.
How to use
- Upload the before and after images.
- Choose slider, overlay or differences.
- Drag the slider or download the result.
When to use it
- Showing editing and retouching results.
- Finding changes between versions of a layout.
- Spot-the-difference games.
Frequently asked questions
How does differences mode work?
Every pixel of the two images is compared. Wherever there is a difference, it shows up in red, and the tool shows the percentage of the image that changed.
Do the images need to be the same size?
No. The second image is fitted to the size of the first, but the comparison is more accurate when both have the same dimensions.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.