Not sure if this helps much:
I don't know that .PNG files have EXIF fields - they only relate to .JPG files, right?
File properties is different - all files will have that, as part of the file system, but I don't know that SC saves anything special to File Properties.
What it does seem to have is some kind of database of its own - not sure where it keeps it - which also seems to be able to filch metadata from other proggies - e,g,, from CHS (ClipboardHelpAndSpell). But I don't think that's saved in, nor does it travel with .PNG files (unless it's say an ADS - AlternativeData Stream?).