How did you make one binary image file for navio?

Could you let me know how to make image file for raspberry pi that Navio is mounted on?
I’m just want to make the build environment to get output img file like your emlid-raspberrypi2-raspbian-rt-20150401.img whenever I modify some files
What tools did you use to make the img file? linux command…?
Thanks in advance.

After modification you can save your image by using dd in Linux or some utility on Windows.
Check this tutorial: