Hi all together,
I’m a Rookie on Linux, so don´t be angry with me 
Problem:
Installed Dietpi, done Settings, all ok.
Wrote down the .img with Win32Diskimager for flashing (a lot of) other devices.
On the Masterdevice was only one Partition with <30GB,
so the Image has this size too and Rufus needs nearly 45 minutes to flash.
Is it possible to downsize the Partition on a running system, what will make the
Image smaller ?
Smaller Image = faster Flash?!
theoretically this is possible, but you need a 2nd Linux box where you can connect your SD card to. Like a VM or other SBC. There you could run our imager tool to create a compressed image from SD card.
Thank you for your fast response.
I’ll try it an give you feedback about it
Sorry for the late answer.
I killed the system with my test.
The problem is that the Pi is running behind a firewall (inside our company).
So i ain´t able to install anything from the net…