Wangdü - common abbreviated title of the prayer 'The Great Cloud of Blessings: The Prayer which Magnetizes All that Appears and Exists' by Mipham Rinpoche
The prayer flag contains both images and prayers. In the prayer flag flown at Rigpa centres the images are of the deities mentioned in the prayer and are based on an print of a thangka given to Sogyal Rinpoche by Khenpo Jigphun. Khenpo Jigphun flew many wangdu prayer flags around his monastery. Previously this prayer flag has not been widely distributed and was considered secret or, maybe, personal.
The central deity is Pema Gyalpo. For the Rigpa flag we used the Nirmanakaya form. Khenpo Jighun's image has a Sambhogakaya form. Above are Vajradharma and Amitabha. Avalokiteshvara, as Padmapani and Hayagriva are top left and right. Then there are three dakinis, Guhyajñana, Vajravarahi and Kurukulla, and then Döpé Gyalpo.
Normally mantras and prayers are the main feature of prayer flags, rather than images, so it is the prayer that is the main thing. Indeed, as it says in the text.
Recently this image has been printed in the Rigpa Calendar, following advice that this would be beneficial.
Usually it is printed on red cloth.