This should clear up any casting concerns:
Cast: Daniel Radcliffe (Harry Potter), Emma Watson (Hermione Granger), Rupert Grint (Ron Weasley), Gary Oldman (Sirius Black), David Thewlis (Professor Remis Lupin), Peter Best (MacNair), David Bradley (Argus Filch), Julie Christie (Madam Rosmerta), John Cleese (Nick the Nearly Headless Ghost), Robbie Coltrane (Rubeus Hagrid), Alfie Enoch (Dean Thomas), Tom Felton (Draco Malfoy), Pam Ferris (Aunt Marge), Dawn French (The Fat Lady), Michael Gambon (Professor Albus Dumbledore), Jimmy Gardner (Ernie Prang), Richard Griffiths (Uncle Dursley), Joshua Herdman (Gregory Goyle), Matt Lewis (Neville Longbottom), Hugh Mitchell (Colin Creevey), Devon Murray (Seamus), Katharine Nicholson (Pansy Parkinson), Chris Rankin (Percy Weasley), Alan Rickman (Professor Snape), Fiona Shaw (Aunt Petunia), Maggie Smith (Prof. Minerva McGonagall), Timothy Spall (Peter Pettigrew), Jim Tavare (Tom, the Leaky Cauldron Innkeeper), Julie Walters (Mrs. Weasley), Jamie Waylett (Vincent Crabbe), Paul Whitehouse (Sir Cadogan)
Cast: Daniel Radcliffe (Harry Potter), Emma Watson (Hermione Granger), Rupert Grint (Ron Weasley), Gary Oldman (Sirius Black), David Thewlis (Professor Remis Lupin), Peter Best (MacNair), David Bradley (Argus Filch), Julie Christie (Madam Rosmerta), John Cleese (Nick the Nearly Headless Ghost), Robbie Coltrane (Rubeus Hagrid), Alfie Enoch (Dean Thomas), Tom Felton (Draco Malfoy), Pam Ferris (Aunt Marge), Dawn French (The Fat Lady), Michael Gambon (Professor Albus Dumbledore), Jimmy Gardner (Ernie Prang), Richard Griffiths (Uncle Dursley), Joshua Herdman (Gregory Goyle), Matt Lewis (Neville Longbottom), Hugh Mitchell (Colin Creevey), Devon Murray (Seamus), Katharine Nicholson (Pansy Parkinson), Chris Rankin (Percy Weasley), Alan Rickman (Professor Snape), Fiona Shaw (Aunt Petunia), Maggie Smith (Prof. Minerva McGonagall), Timothy Spall (Peter Pettigrew), Jim Tavare (Tom, the Leaky Cauldron Innkeeper), Julie Walters (Mrs. Weasley), Jamie Waylett (Vincent Crabbe), Paul Whitehouse (Sir Cadogan)