We have been working along with the K12 Biology core. We have found some good graphics in the references section of each unit. The links to outside webs could be improved. For example--
I found a great one on cells that is provided by the National Human Genome Research Institute.
There are three tabs, one is an illustration, one is in 3-D Animation and in the top right hand corner there is audio.
photo: National Human Genome Research Institute