What are you using to save the image? If you right click the image from MAX, are you able to save a bmp from there?
Also, there is a great example on ni.com that you may not have seen yet that shows how to save images without Vision. It can be found by typing "save images without vision" into the main search field of ni.com. It is called Saving Images Without IMAQ Vision (IMAQ Only) and has examples for LabVIEW, CVI, and Visual Basic.