OscarVogel was very recently heard to utter:
So, how can I correctly REPLACE an image in Publisher with a copy of
an image from Photoshop?"

Do not copy and paste. (This is generally bad practise, as well as causing
your problem)

Export a PNG file from Photoshop; then in Publisher, right-click your
current picture, go to Change Picture From File..., and select your PNG
file.

--
Ed Bennett - MVP Microsoft Publisher