Well, I just learned that the .tex file that I have been laboring over can be imported into LyX, and it produces upon request the same document as does pdflatex (no wonder here though, since LyX must be orchestrating execution of pdflatex), with the erroneously presented graphic image.
So, Dominik, did you have some suggestion for me regarding the insertion of graphics (PDFs) into my document with the assistance of LyX? wrb