Why use this image overlay tool?
This free online image comparison tool lets you overlay two pictures and instantly see their differences. It runs entirely in your browser — no sign-up, no uploads to any server, and no watermarks. Designers, developers, photographers, and QA testers can use it to verify pixel-perfect implementations, spot visual regressions, compare photo edits, and align design mockups.
- Privacy-first: 100% client-side; your images never leave your device.
- Adjustable opacity: Fade the overlay from 0% to 100% to reveal differences gradually.
- Blend modes: Use Difference to instantly highlight any mismatched pixels.
- Drag, stretch & zoom: Freely move, resize, or stretch the overlay; Shift-drag to keep aspect ratio.
- Hide overlay: Quickly toggle the second image off to confirm the base without removing state.
- Bilingual: English and Simplified Chinese interface.