There are four subjects per sheet inside the 20-stamp booklets. Two stamps per page are vertical, two horizontal. Here’s what I’ve been told is the list of stamp subjects:
The first pane is from the first film. The stamps show Harry receiving his acceptance to Hogwarts; Harry and Ron; Harry, Ron and Hermione; and Hermione.
The second pane shows Harry and some of the creatures in the stories, including Hedwig, his owl.
The subjects in the third are all Hogwarts instructors: Dumbledore, Snape, McGonagall, and Hagrid. It appears the stamp shows Michael Gambon as Dumbledore, not Richard Harris, who died a few weeks before the release of the second film.
The fourth pane has a picture of Hermione, Harry and Ron; Ginny Weasley, Fred and George Weasley, and Luna Lovegood.
And in the fifth, we’ll find pictures of Harry and Voldemort in battle (the former design has already been released publicly and is shown here), Draco Malfoy, and Bellatrix Lestrange. The latter strikes me as a (le)strange choice, because I don’t think she’s a major character. I would have picked Neville Longbottom for one of the stamps, or, if pressed for a female character, Molly Weasley or, even better if they wanted a female villain, Dolores Umbridge.
There is a red sealing wax seal in the blank space in the middle of each pane. There’s a picture of Hogwarts (castle) one another page of the booklet.
BTW. the stamps are the usual standard commemorative size, about 1.56″x0.89″, so I calculate that a pane from the booklet (4 stamps) is about 4 inches on a side.
Variety, the entertainment trade paper, asks whether these Harry Potter Stamps will succeed where The Simpsons stamps failed. Click here for that article: http://variety.com/2013/film/news/will-harry-potter-stamps-succeed-where-the-simpsons-failed-1200827306/
The choice of Bellatrix Lestrange makes sense. That pane features battles with villains, so substituting another “good” female character like Molly Weasley wouldn’t serve. The character of Dolores Umbrage is evil but in more of a bureaucratic / autocratic way; she doesn’t really “do battle” the way other characters do. Further, Umbrage really only figures in one book, whereas Bellatrix appears in most if not all of them.
Or so my children tell me…