core-image-nas-intel-corei7-64.iso is the image targeted for Intel architecture platform such as Core i7 or Atom architecture.
The format of core-image-nas-intel-corei7-64.iso is a usb image.
To use it,you need to flash on to an usb device.
core-image-nas-raspberrypi.rootfs.rpi-sdimg is the image targeted for Rapberrypi platform (Model I).
core-image-nas-raspberrypi2.rootfs.rpi-sdimg is the image targeted for Rapberrypi platform (Model II).
To use them,you need to flash on to an sdcard device.
For flashing the image you can use dd command as for example
sudo dd if=/<path_to_image>/core-image-nas-intel-corei7-64.iso of=/dev/sdX
sudo dd if=/<path_to_image>/core-image-nas-raspberrypi.rootfs.rpi-sdimg of=/dev/sdX
The default user name / password are:
user : meta-nas
password : meta-nas