Image Comparison Slider

What Is an Image Comparison Slider?

An image comparison slider places two images in the same frame and lets you drag a divider to reveal one over the other. It is the fastest way to judge a before and after change, because your eye compares the exact same region of both images instead of jumping between two windows. This tool keeps both uploads in your browser: drop in an image A and an image B, then drag the handle or use the slider beneath the viewer.

When to Compare Two Images

• Checking compression quality. Compare an original against a compressed export to confirm that file size savings did not introduce visible blocking, banding, or soft detail.
• Reviewing photo edits. Retouching, color grading, and background replacement are much easier to evaluate when the before and after align pixel for pixel.
• Design iteration reviews. Show a client exactly what changed between two design rounds with an interactive instead of two static attachments.
• Website and app regression checks. Compare screenshots of the same page before and after a change to confirm that only the intended areas moved.
• Ecommerce product photos. Pick the better angle, lighting setup, or retouch by flipping between candidates in place.

How to Use the Slider

1. Upload the original or earlier version as Image A (Before).
2. Upload the edited or newer version as Image B (After).
3. Drag the divider left and right, or use the range control under the viewer, to sweep between the two versions.
4. Switch to side by side mode when the images have different dimensions or when you want both versions fully visible at once.
5. Use Swap Images if the before and after are the wrong way round, and Remove All to start over with new files.

Slider View Versus Side by Side

The slider mode overlays both images and is the right choice when the two files share the same dimensions or the same framing. Because the divider reveals one image over the other, your eye picks up small differences in sharpness, color, and exposure that are easy to miss in a side by side layout. The side by side mode shows both images at full width and is better when the images have different aspect ratios, when one is a crop of the other, or when you want to inspect each version as a whole. Both modes are available from the toggle above the viewer, and neither re-encodes your files.

What the Viewer Shows

Each upload reports the file name, file size, and pixel dimensions once the image loads, so you can confirm at a glance that you are comparing the right exports. The comparison itself draws the two images using the browser's native image rendering, which means the appearance in the viewer matches the appearance of the files themselves. No resizing, filtering, or re-compression is applied to either image.

Privacy

Images are loaded from local object URLs created on your device. Nothing is uploaded to a server, and the object URLs are revoked when you replace an image or close the page. The tool is safe for unreleased designs, client work, and private photos, and it keeps working offline after the page loads.

Related Tools

Continue your image workflow with these tools:

• Image Compressor
• Image Resizer
• Image Filters
• Image Color Picker
• Image Metadata Viewer
• Image to Base64