Before-and-after comparisons are the most convincing way to show an edit, a restoration, or a redesign, and a slider that wipes between two images communicates the difference instantly. This tool lets you upload a before image and an after image, then drag a slider to reveal each side, with the split position shown as a percentage. It runs entirely in your browser, so the images are never uploaded, and it works with any two images of the same subject, from photo edits to website redesign screenshots. The comparison is visual and immediate, which is why sliders beat side-by-side pairs for spotting subtle changes: the eye tracks the boundary as it moves across the image. The slider also works well in reviews, where showing a colleague exactly where an edit changed an image settles debates faster than describing it.
Quick Answer: Upload a before and an after image, then drag the slider to compare them.
Free Online Tool
Image Compare Slider
Drag the line, watch the change.
How to Use the Image Compare Slider
- Upload the before image.
- Upload the after image.
- Drag the slider to wipe between the two versions.
- Read the split percentage to describe the comparison.
- Screenshot the slider position you want to share, if needed.
Key Features
- Before and after images in one comparison view.
- Draggable slider with live percentage readout.
- Works with any two images of the same subject.
- Private local previews with no uploads.
- Simple, focused comparison with no editing features.
Best Practices and Tips
- Use images of the same size and framing; mismatched images make the slider boundary misleading.
- Align the subject identically in both images so the wipe reveals changes, not camera movement.
- For photo edits, export the before and after at the same dimensions from the same editor.
- Move the slider slowly across areas of interest; fast drags hide subtle differences.
- The percentage readout helps when describing a comparison to someone else, such as the point where a flaw disappears.
Common Mistakes to Avoid
- Comparing images of different sizes, which makes the slider comparison meaningless.
- Uploading the same image twice and wondering why the slider shows no change.
- Expecting the tool to save or share the comparison; it is a viewer, so screenshot the result to keep it.
- Using unrelated images, where a slider wipe communicates nothing.
Frequently Asked Questions
How does the slider work?
The two images are stacked, with the before image on top clipped to the slider position and the after image beneath. Dragging the slider moves the clip boundary, revealing more of one image and less of the other, with the percentage showing how much of the before image is visible.
Do the images need to be the same size?
They should be, for a meaningful comparison. If they differ, the display scales them to a common preview size, but framing differences will still show as shifts at the boundary, so matching size and framing before uploading gives the cleanest result.
Can I share the comparison?
The tool itself is a viewer, so to share a particular comparison, take a screenshot at the slider position you want. The images themselves are never uploaded, so there is no share link to generate.
What is it good for?
Photo retouching, restoration work, design revisions, renovation photos, and any task where the difference between two versions of the same subject is the story. It is also useful for quality control, catching edits that went too far.
Is anything uploaded?
No. Both images are previewed locally in your browser using object URLs, and no file is sent to any server.