Image Comparison Tool
Upload two images and compare them with an interactive slider that reveals one over the other as you drag. Perfect for before/after edits, compression tests, design variants, and spotting changes that are too subtle to see in side-by-side thumbnails. Works on any two images of the same or different sizes — both are scaled to fit the comparison frame.
How to compare two images
- Upload your first image — this becomes the left (or before) side of the comparison.
- Upload your second image — it loads as the right (or after) overlay.
- Drag the slider left and right over the combined view to reveal more of one image or the other. Move slowly over the area you want to inspect closely.
- Zoom your browser or take a screenshot if you need to share the comparison in a review, bug report or social post.
Common use cases
- Comparing a photo before and after an edit to check that colour grading or retouching is subtle enough.
- Benchmarking image compression at different quality levels to see where artefacts become visible.
- Reviewing AI upscaling or denoising results against the original to judge real detail gained versus invented texture.
- Spotting differences between two design mocks or exported UI screens that look identical at first glance.
Frequently asked questions
Do both images need to be the same size?
No. The tool scales both images to fit the comparison frame. For the cleanest comparison, though, matching dimensions give a pixel-accurate overlay with no resampling.
Can I export the comparison as a single image?
This tool is focused on interactive inspection. For a static export, take a screenshot of the browser window or use the built-in screenshot feature in your OS.
Are my images uploaded to a server?
No. Both images are loaded into the browser and composited with Canvas locally. Nothing leaves your device and no copies are stored.
Why does one image look scaled or pixelated?
If the two images have very different dimensions, scaling to the common frame can introduce softening or pixelation on the smaller one. Use matching resolutions for the sharpest comparison.
About image comparison
Side-by-side slider comparison is the most intuitive way to inspect differences between two versions of an image, because your eye judges the change at the exact pixel boundary where the slider sits, rather than having to mentally swap between two views. It is widely used in photo editing, image compression benchmarks, AI upscaler demos, and UI design reviews where small colour and contrast shifts matter more than obvious layout changes.
- Interactive slider that drags left and right
- Accepts two images of any format or size
- Auto-scales both to the comparison frame
- Clean overlay with no watermark or branding
- Runs entirely in the browser with Canvas
- Your images never leave your device
Free. No signup. No file uploads. Ads via AdSense (consent required).
By Marco B. ·