In "Scandal in Bohemia", who is Irene Adler and how does Holmes think Irene will show him where the picture is?

Irene Adler appeared in the first Sherlock Holmes short story "A Scandal in Bohemia." The King of Bohemia approaches Holmes and tells Holmes that he, the King, is afraid that Irene will reveal their previous relationship or blackmail him for money, since a photograph of them as a couple was taken, and he is now engaged to another woman. Holmes then goes to her home, and in p lan to discover the photo, finds out that she soon leaves for the US with the photo and has no reason to cause any harm to the King. Holmes later refers to her as "the woman" in other places in the series.