Cameras and phones write EXIF metadata into each photo: the camera model, the lens, exposure settings, the capture time and often GPS coordinates. Photographers use it to learn from their settings, but the same data tells anyone who receives the original file where and when it was taken.
This viewer reads the metadata in your browser and lists the fields that are present. Screenshots, many edited exports and images passed through messaging apps have little or no EXIF, and the viewer says so instead of showing an empty table.
If location data is present, the page shows a warning. The download button redraws the photo on a canvas, which discards EXIF and GPS, and saves a new copy you can share.