Q: What is the maximum number of disk images that can be switched?
A: It is 10 for one drive. But the total number must not exceed 16. For example, you have A00, A01...A09, then the disk images for Drive B can only be B00, B01....B05. Otherwise the disk swithcing will not work properly.
Q: There is one mysterious button that you say can store Disk Image, what does it do in detail?
A: When you load disk image from USB flash drive or from Bluetooth, it actually convert the disk image (.DSK format) to nibble format like a real APPLE DOS uses and store it to a volitile RAM. Actual disk read/write operations are using this RAM. So when you exit iDisk menu and enter Apple II operation, any change you made (such like DOS command SAVE)
only change the content of the RAM. In order to save the disk to USB flash drive, unfortunately, you don't have chance to go back to iDisk menu to save it, so that a button is provided to do that. Only when you press that button, any changes you made is saved permenatly on the USB flash drive. Otherwise, the change will disappear once you turn off the Apple II power.