added connection images to README.md

Author: cristidragomir97

README.md

@@ -20,7 +20,9 @@ This library provides a toolkit for interacting with the official Arduino 4G Mod
 1. Insert your Arduino 4G module to the Arduino Portenta Mid Carrier
 2. Insert a valid SIM card either on the back of the Arduino 4G miniPCI board, or the **PCIE_SIM** connector on the Portenta Mid Carrier
 3. Connect the 6 **SERIAL1** header pins to their corresponding pins on the **PCIE_BREAKOUT** header using jumpers
+![](https://raw.githubusercontent.com/arduino-libraries/Arduino_Cellular/main/extras/connection_img/header.jpg)
 4. Connect the **3V3 PCIE** pin to the **3V3 Buck** 
+![](https://raw.githubusercontent.com/cristidragomir97/Arduino_Cellular/main/extras/connection_img/buck.jpg)
 5. Connect external power to the Mid Carrier, via the **VIN** (5-12V) because modem use a lot of power when connecting or getting a GPS location. Make sure your supply can handle around 3A. 
 6. Get the APN settings from your network operator and add them to the "ArduinoSecrets.h" file for each sketch
 ```c