I have a lot of trouble with pictures on the web too. The small details are just often not there, esp. when two or more species have a lot in common. Trey Sanders (Friends of dendrochilum.com) says that many pictures of dendrochilum on the web are mislabeled. He also says that many plants tagged as cobbianum are really other species. Whats a poor girl to do.
I sent photos to Trey and he confirmed my plant is a dendrochilum latifolium var. macranthum. He says they are quite variable. My "magnum" is most likely a latifolium variation also, since a true Magnum in the trade would be very rare. Flickr: noble's memory's Photostream