Synchronize zoom and pan to inspect shifts, transparency and edges on a shared background.
Enable JavaScript for interactive processing. You can read the instructions, limits, and FAQs below without it. Files are processed only in your browser.
Dual Image Overlay Comparator User Guide
Load two static PNG or JPG images with matching EXIF-normalized dimensions locally, then compare them using shared coordinates, zoom, pan and background in split or crossfade views.
How to use
Import images A and B, then check their formats, names, file sizes and EXIF-normalized decoded dimensions.
Switch between split view and crossfade, using the B percentage to inspect full A at 0%, full B at 100% and intermediate views.
Choose actual size or fit to viewport, zoom and drag both images together, and inspect transparency on a checkerboard, black or white background.
Formats and limits
Each file may be up to 20 MiB, 8,192 px per side and 12 million pixels (1,200 × 10,000). The pair may total up to 24 million pixels / an estimated 96,000,000 RGBA bytes. Only static PNG/JPG images are accepted.
The two EXIF-normalized decoded widths and heights must match exactly. Images are not automatically aligned, stretched, cropped, padded or rotation-corrected. Zoom is limited to 25–400%.
The display depends on this browser's decoding, color management, alpha premultiplication, device pixel ratio and interpolation. It is not a raw-sample, precision ICC, pixel-difference, forensic or exact-match test.
Output
Only a local visual preview is provided for the current page. Images are not modified, uploaded, persisted or exported, and the tool does not score results or guarantee detection of every difference.
Frequently asked questions
Why is the background composited before crossfading?
A and B are each composited onto the same checkerboard, black or white background before the two complete views are blended. At 100% B, transparent areas therefore show only the selected background and never reveal A.
Why are two images rejected when their pixel dimensions appear to match?
The tool uses dimensions decoded after the browser applies EXIF orientation. Width and height must match exactly, and both files must pass file-size, side, pixel and combined-memory limits.
File names and content are processed only in your browser and are not sent to a server. This preview-only tool creates no export file; leaving it clears the current images and view.