[Q] How to make a rom backup (from rom manager) to become a flashable version of CWM?

I've just flash a rom (download from xda, which is in *.zip format JB4.12) by CWM to my note 1, successfully.

Now I've just backup the rom, with some apps and data, by rom manager. However, the backup come with several files include a *.img instead of a zip file.

Anybody know, how can I make these files to become one *zip file, which I can flash it to the system and make it become factory default??

Please help...