Add flashing Armbian images section to user guide

Added instructions for flashing Armbian images from a running system.

Author: igorpecovnik

docs/User-Guide_Getting-Started.md

@@ -395,6 +395,19 @@ For novice users, a sensible default is `ext4`.
 
 Congratulation. You have successfully installed Armbian onto your board!
 
+## Flashing Armbian images from a running system
+
+!!! note
+    Armbian also provides a tool to **download, verify, and flash OS images**
+    directly to SD cards, USB drives, eMMC, SSD, or NVMe storage — without using
+    another computer.
+
+    This is useful when:
+    - preparing new boot media  
+    - reinstalling or recovering a broken system  
+    - switching to another Armbian variant or kernel branch  
+
+    [The tool](/User-Guide_Armbian-Config/System/#download-and-flash) works on any device running **Armbian** or any compatible **Debian/Ubuntu** system.
 
 ## Update the system