In SS13 we gonna build our own station. I do want to make button in Admin panel that save current map as a DMM file.

I have no idea how to do this. Where should I begin?
In response to Kozuma3
Thank you but i dont think so. Its only image
In response to LeserZ
For what it's worth, dmis are just pngs. You could change the file extension and have a working dmi file.
In response to Spevacus
oh my bad i meant dmm not a dmi
In response to LeserZ
This library has a .dmm writer:

However, the DMM format is very limited. Unlike savefiles, non-constant variables can't be written. The library doesn't support all types of DMM-writable values. But, it's probably worth a shot.