Updated Protocol and compatibility (markdown)

Protocol-and-compatibility.md

@@ -11,7 +11,7 @@
 ## APRS AX.25 UI packet format
 At the link level, APRS uses the AX.25 protocol, as defined in AmateurPacket-Radio Link-Layer Protocol, utilizing Unnumbered Information (UI) frames exclusively. This means that APRS runs in connection less mode, whereby AX.25 frames are transmitted without expecting any response, and reception at the other end is not guaranteed.At a higher level, APRS supports a messaging protocol that allows users tos end short messages (one line of text) to nominated stations, and expects to receive acknowledgements from those stations.
 
-![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/images/ax25.png)
+![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/extras/images/ax25.png)
 
 - **Flag** — The flag field at each end of the frame is the bit sequence 0x7e that separates each frame.
 - **Destination Address** — This field can contain an APRS destination callsign or APRS data. APRS data is encoded to ensure that the field conforms to the standard AX.25 call sign format (i.e. 6 alphanumeric characters plus SSID). If the SSID is non-zero, it specifies a generic APRS digipeater path.
@@ -23,15 +23,15 @@ At the link level, APRS uses the AX.25 protocol, as defined in AmateurPacket-Rad
 - Frame Check Sequence — The FCS is a sequence of 16 bits used for checking the integrity of a received frame.
 
 ## APRS data in AX.25 information field
-![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/images/aprs_information.png)
+![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/extras/images/aprs_information.png)
 
 ## APRS position packet
-![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/images/aprs_position.png)
+![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/extras/images/aprs_position.png)
 
 ## APRS compressed packets
 In compressed data format, the Information field contains the station’s latitude and longitude, together with course and speed or pre-calculated radio range or altitude. This information is compressed to minimize the length of the transmitted packet (and therefore improve its chances of being received correctly under less than ideal conditions). The Information field also contains a display Symbol Code, and there may optionally be a plain text comment (uncompressed) as well.
 
-![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/images/aprs_compressed.png)
+![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/extras/images/aprs_compressed.png)
 
 ## APRS compressed packets generation
 Arduino code to generate compressed coordinates from degrees.