.img

[tsamouri]

how to meka files in .img ?

[pickledfrog]

a great program to use is imgburn it free and opensource available from The Official ImgBurn Website (http://imgburn.com) or search on sourceforge.net

or do you mean the image format

[pickledfrog]

sorry just realized you may have meant the .img thats loaded as a ramdisk when linux is booted.
this is created and edited form command line, what are trying to do, give us a clue?