How to make screen sharing application with standard modules?

I need to make a screen sharing application with the standard python modules. I do not have PIL and cannot download any additional modules.

I will be sending the data within one network on windows and plan to take screenshots, somehow compress them, send them to a folder and have person B access that folder (since they are on the same network) to repeatedly open/refresh, uncompress, and see the images.

Where can I start?