Add the pre-built image.

README.md

@@ -31,3 +31,20 @@ Those settings are recommended by the RaspberryPi instructions.
  
 ## controlling your radio via web interface
 You can control your radio via web interface: find its IP and in your browser enter `http://[IP of your radio]:8080` with no username and password `raspberry`.
+
+## ready-to-flash image
+Out of security concerns I recommend you read the [code](https://github.com/RPi-Distro/pi-gen/compare/master...pirateradiohack:master) and build the image yourself.  
+But, if you prefer to trust a stranger on the Internet with your Pirate Radio, for your convenience you will find the latest image pre-compiled here: [2019-05-23-Piradio-lite.img](https://github.com/pirateradiohack/PiRadio/releases/download/2019-05-23-PiRadio/2019-05-23-Piradio-lite.img) . Just flash it
+and configure your wifi. You can also optionally configure your own radio streams playlist.
+
+The files to edit are:
+- wifi: `/etc/wpa_supplicant/wpa_supplicant.conf` (edit this file)
+- playlist: `/home/pi/.config/vlc/playlist.m3u` (create this file)
+
+You can edit them before or after flashing the image:
+- before flashing you can mount the `.img`.  
+With a modern operating system you probably just have to click the .img.  
+With Linux you can use `kpartx` (from the `multipath-tools` package) to be able to mount the partition directly: `sudo kpartx -a path/to/2019-05-23-Piradio-lite.img` followed by `sudo mount /dev/mapper/loop0p2 tmp/ -o loop,rw`  
+(you will need to create the mount directory first and check what loop device you are using with `sudo kpartx -l path/to/2019-05-23-Piradio-lite.img`). Then you can edit the files mentionned above. And `sudo umount tmp`.  
+You are safe to flash the image.
+- after flashing your operating system probably automounts the partitions.