I have used PhotoShop to add titles and other information to some of my
images.

I can also use Windows Explorer (XP), right click on an image and choose
Properties / Summary tab. Box pops up with title BLANK, rest of the
information, like comments, are also blank. Little surprising. I figured
that PS and Explorer would be dealing with the same "title" metadata at
least. I can enter another "title" using Explorer. So now there are two
titles associated with one image

How many independent kinds of JPEG metadata are there? I know about EXIF.

DaveCu