The writer note the armor to be done by an artist/craftsman. Usually when we picture a hero we see them dressed heroically. He then proceeds to flatter himself for his achievements as a youth.
The main idea of this text is how a wildlife photographer nearly did not succeed in snapping a valuable shot of a deer in the woods.
The clues given in the text are elements of suspense like "very slowly", "carefully", and "holding my breath". There are also time indicators such as "just as I was..." and "an instant later".
The clues listed above give the impression that the narrator was likely to fail and under temporal pressure. They make the author's pride after this stressful feat perceivable in the text.
The last line conveys the importance of this photograph to the author by mentoning that it is now printed out, "framed" and displayed as decoration in the author's house ("hangs above our fireplace").