The Introduction describes it best, but the basic idea is to avoid English translation by matching images with Spanish sounds and to have fun doing it. Emphasis is on Infinitive use and the sound-combinations of the simple Present Tense. Imágenes de sonido is not for the solitary learner--could be--but it is best designed for in-class interaction, and as such, Imágenes de sonido works best in pairs and in groups.
It merely takes a little memorization and a little imagination to get one through it. Enjoy!