Many new stills, studio shots, and set photos from Order of the Phoenix (including Harry at the atrium; the students in Hogsmeade; Dumbledore's Army and more) and Half-Blood Prince (featuring Quidditch tryouts, the twins' joke shop, and Harry in Potions) have been released and can be found in high resolution here and here.

Half-Blood Prince:



















Order of the Phoenix:















Source: Oclumencia