CThruView Transparent Image Viewer - CThruView is a free transparent image viewer that allows mouse clicks to go through the image.
Jimpl - Free online photo metadata and EXIF data viewer. Uncover hidden data of your pictures. Upload a photo to find where, when, and how it was taken.
LayerX - An intuitive app to display transparent images on screen.
Metadata++ - Homepage of Metadata++, free, intuitive and powerful EXIF, IPTC, XMP, ICC, GPS viewer/editor.
Osiva - Osiva" is an acronym that stands for "Overly Simple Image Viewing
ExifToolGUI - Graphical user interface to https://alternativeto.