Free Online Image Diff Tool — Compare Images Side by Side
Compare two images with our free online image diff tool. Upload your before and after images and choose from three comparison modes: side-by-side view for a straightforward comparison, a draggable slider overlay to scrub between the two images, or pixel-difference highlighting that shows exactly what changed. Perfect for designers reviewing revisions, photographers comparing edits, developers checking visual regressions, or anyone who needs to spot differences between two images. All processing happens locally in your browser.
Upload the first image (before) and the second image (after) you want to compare.
Choose a comparison mode: side-by-side, draggable slider, or pixel difference.
Analyze the differences, use the slider to scrub between versions, or download the diff result.
Tips for Comparing Images
- Use images of the same dimensions for the most accurate pixel-diff results. Differently sized images will be normalized to the smaller canvas.
- The slider mode is great for subtle changes — slowly drag the handle back and forth to spot small differences.
- The difference mode uses a color highlight (magenta/red) to draw attention to changed pixels. Adjust the intensity to reduce noise on complex images.
Frequently Asked Questions — Image Diff Tool
Is the image diff tool free?
Yes, completely free. No registration, no hidden charges, and no watermarks. All processing happens locally in your browser.
What image formats are supported?
The tool supports all common image formats including JPG, PNG, WebP, GIF, BMP, AVIF, SVG, and more.
What if my images are different sizes?
The tool automatically normalizes images by centering each on a shared canvas. However, for the most accurate pixel-diff results, we recommend uploading images that are the same dimensions.
What do the colors in difference mode mean?
In difference mode, pixels that are different between the two images are highlighted with a magenta (or red, depending on intensity) overlay. Unchanged pixels appear in grayscale. This makes changed areas instantly visible.
Can I save the comparison result?
Yes! In difference mode, you can download the diff result as a PNG image showing exactly what changed between the two images.
Is this useful for web development?
Absolutely. Web developers can use it to compare design iterations, verify CSS changes, check responsive layout differences, or validate image optimization output. The slider mode is especially helpful for demonstrating subtle UI improvements to clients.
Do you support batch comparison?
The tool compares one pair of images at a time. For comparing multiple image pairs, simply upload new images — the tool will clear and reload instantly.