Image comparison guide
Compare images by choosing the right view
Image comparison online works best when you match the view to the decision you need to make. A design review, product retouch, UI screenshot check, and pixel difference check all ask different questions.
This guide focuses on two image slots, browser-local preview, and four comparison modes for practical review.
Actual examples
See the four comparison modes with local demo images
Each preview uses a real before-and-after pair so you can judge the mode from the kind of image review it is meant to support.
Image A
Image B
Step 1
Start with Image A and Image B
Load the original or before image into Image A. Load the modified or after image into Image B. Keeping that order makes each comparison mode easier to read.
Use files that represent the same scene, design, product shot, or screenshot. If you compare unrelated images, the tool can still display them, but the result will be less useful.
- Image A: original, before, baseline, or reference image.
- Image B: modified, after, exported, edited, or new image.
- Supported formats: PNG, JPG, JPEG, WebP.
Before and after
image comparison slider
image comparison slider helps before/after review for image comparison and comparison picture.
Use this mode when you want to reveal visible edits across one shared image area.
Whole image
side by side image comparison
side by side image comparison keeps both files visible for picture comparison and layout checks.
Use this mode when you need both images visible at once for crop, spacing, and composition review.
Alignment
overlay image comparison
overlay image comparison helps inspect alignment, color, crop, and spacing changes.
Use this mode when placement, scale, or alignment matters more than a simple before-and-after reveal.
Pixel check
Highlight Diff
Highlight image differences in red after the browser-local pixel threshold test.
Use this mode when you need changed areas and local pixel metrics after the diff runs.
Formats
Supported image formats
The current tool supports PNG, JPG, JPEG, WebP files. For best results, compare two images from the same source workflow.
Convert unsupported formats before comparison.
Loaded images
How to tell whether images loaded
If your images appear in the upload slots, they have usually loaded successfully. Very large image files can take longer to load and may slow down comparison.
Use cases
Common uses for image comparison online
Compare two images online when you need to review visual changes clearly before accepting an edit, export, or screenshot.
Mode table
Simple mode table
| Mode | Best for | Use when |
|---|---|---|
| image comparison slider | image comparison slider helps before/after review for image comparison and comparison picture. | Drag the split line after the image diff checker marks where changed pixels sit in context. |
| side by side image comparison | side by side image comparison keeps both files visible for picture comparison and layout checks. | Compare both images at once before reading image difference checker metrics. |
| overlay image comparison | overlay image comparison helps inspect alignment, color, crop, and spacing changes. | Fade one image over the other to spot alignment, color, lighting shifts, and visual differences. |
| Highlight Diff | Highlight Diff calculates browser-local pixel differences only after you run the local diff. | Highlight image differences in red after the browser-local pixel threshold test. |
Ready to compare