Create ".img" file and Mount

I'm recently working on a Android project. I've some files like "busybox", "7za", "zipalign" etc and folders in "/sdcard/myfolder". I want to put these files and folders in a ".img" file and mount it in "/data" or else with a script but I can't figure it out how to do this.

I want to do this because I want to get the Android(EXT4) filesystem feature from "SDCARD" and "busybox" like binaries would works properly, symlinked. :-)

Please help me....