boards: convert images to JPEG and reduce image size

The boards folder uses ~142.8 MB, being the largest in the repository.
This is due mostly to board images, which are in most cases not
optimized for web content. This patch tries to address this problem by
converting all pictures to JPEG (quality 75) and by adjusting its size
up to 750 px (the width of the documentation content). Images that
specified a fixed width in rst files are converted down to that value
instead.

With this patch, folder goes down to ~53.5 MB from 142.8 MB (-~63%).
Note that this patch introduces a new set of binary files to git
history, though (bad).

The process has been automated using this quickly crafted Python script:

```python
from pathlib import Path
import re
import subprocess

def process(doc, image, image_jpeg, size):
    subprocess.run(
        (
	     f"convert {image}"
	     "-background white -alpha remove -alpha off -quality 75"
	     f"-resize {size}\> {image_jpeg}"
	),
        shell=True,
        check=True,
        cwd=doc.parent,
    )
    if image != image_jpeg:
        (doc.parent / image).unlink()

for doc in Path(".").glob("boards/**/*.rst"):
    with open(doc) as f:
        content = ""
        image = None
        for line in f:
            m = re.match(r"^(\s*)\.\. (image|figure):: (.*)$", line)
            if m:
                if image:
                    process(doc, image, image_jpeg, size)

                image = Path(m.group(3))
                if image.suffix not in (".jpg", ".jpeg", ".png"):
                    content += line
                    image = None
                    continue

                image_jpeg = image.parent / (image.stem + ".jpg")
                size = 750
                content += (
                    f"{m.group(1)}.. {m.group(2)}:: {image_jpeg}\n"
                )
            elif image:
                m = re.match(r"\s*:height:\s*[0-9]+.*$", line)
                if m:
                    continue

                m = re.match(r"\s*:width:\s*([0-9]+).*$", line)
                if m:
                    size = min(int(m.group(1)), size)
                    continue

                content += line
                if line == "\n":
                    process(doc, image, image_jpeg, size)
                    image = None
            else:
                content += line

    with open(doc, "w") as f:
        f.write(content)
```

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

boards/arc/em_starterkit/doc/index.rst

@@ -12,8 +12,7 @@ for the ARC EM Family of processors. The EM Family includes the EM4, EM6,
 EM5D, EM7D, EM9D, and EM11D cores. The Zephyr RTOS can be used with the
 EM Starter Kit.
 
-.. image:: ./em_starterkit.jpg
+.. image:: em_starterkit.jpg
-   :width: 442px
    :align: center
    :alt: DesignWare(R) ARC(R) EM Starter Kit (synopsys.com)
 

boards/arc/emsdp/doc/index.rst

@@ -12,8 +12,7 @@ to accelerate software development and debug of ARC EM processors and subsystems
 a wide range of ultra-low power embedded applications such as IoT, sensor fusion,
 and voice applications.
 
-.. image:: ./emsdp.jpg
+.. image:: emsdp.jpg
-   :width: 650px
    :align: center
    :alt: DesignWare(R) ARC(R) EM Software Development Platform (synopsys.com)
 

boards/arc/hsdk/doc/index.rst

@@ -14,8 +14,7 @@ UART, I2S, ADC, PWM and GPIO. A Vivante GPU is also contained in the ARC
 Development System SoC. This allows developers to build and debug complex
 software on a comprehensive hardware platform
 
-.. image:: ./hsdk.jpg
+.. image:: hsdk.jpg
-   :width: 650px
    :align: center
    :alt: DesignWare(R) ARC(R) HS Development Kit (synopsys.com)
 
@@ -110,8 +109,7 @@ The functionality of the Pmod connectors is programmable and includes GPIO, UART
 The location of the pins on the Pmod connectors is shown in Figure below. Detailed pin descriptions
 depending on the pin multiplexer settings are provided in the subsequent sections.
 
-.. image:: ./pinout_diagram_of_the_pmod.jpg
+.. image:: pinout_diagram_of_the_pmod.jpg
-   :width: 442px
    :align: center
    :alt: Pinout Diagram of the Pmod
 
@@ -211,8 +209,7 @@ Mikrobus
 The ARC HSDK features a set of MikroBUS headers. Figure below shows the relevant function assignments,
 fully compatible with the MikroBUS standard. Table below shows the pin assignment on the I/O Multiplexer.
 
-.. image:: ./mikrobus_header.jpg
+.. image:: mikrobus_header.jpg
-   :width: 650px
    :align: center
    :alt: mikrobus header
 
@@ -246,8 +243,7 @@ the ARC HSDK board is fixed to 3V3. Note that the ICSP header is also not availa
 shields do not require this ICSP header as the SPI master interface on this ICSP header
 is also available on the IO10 to IO13 pins.
 
-.. image:: ./arduino_shield_interface.jpg
+.. image:: arduino_shield_interface.jpg
-   :width: 442px
    :align: center
    :alt: arduino shield interface
 

boards/arc/iotdk/doc/index.rst

@@ -14,8 +14,7 @@ implementation of the ARC Data Fusion IP Subsystem running at 144 MHz on
 SMIC's 55-nm ultra-low power process, and a rich set of peripherals commonly
 used in IoT designs such as USB, UART, SPI, I2C, PWM, SDIO, and ADCs.
 
-.. image:: ./iotdk.jpg
+.. image:: iotdk.jpg
-   :width: 650px
    :align: center
    :alt: DesignWare(R) ARC(R)IoT Development Kit (synopsys.com)
 

boards/arm/96b_aerocore2/doc/index.rst

@@ -13,7 +13,6 @@ boards. It can also be used as a standalone board.
 
 
 .. figure:: img/96b_aerocore2.jpg
-     :width: 487px
      :align: center
      :alt: 96Boards Aerocore2
 

boards/arm/96b_argonkey/doc/index.rst

@@ -13,9 +13,7 @@ This board acts as a sensor hub platform for all 96Boards compliant
 family products. It can also be used as a standalone board.
 
 .. figure:: img/96b_argonkey.jpg
-     :width: 540px
      :align: center
-     :height: 558px
      :alt: 96Boards Argonkey
 
      96Boards Argonkey

boards/arm/96b_avenger96/doc/index.rst

@@ -41,10 +41,8 @@ core. Zephyr OS is ported to run on the Cortex®-M4 core.
     - 1x Yellow WiFi LED
     - 1x Red power supply LED
 
-.. image:: img/96b_avenger96.png
+.. image:: img/96b_avenger96.jpg
-     :width: 1027px
      :align: center
-     :height: 1217px
      :alt: 96Boards Avenger96
 
 More information about the board can be found at the

boards/arm/96b_carbon/doc/index.rst

@@ -35,8 +35,7 @@ After you have flashed your nRF51, you can perform basic validation
 of this Bluetooth setup using the instructions
 :ref:`below <96b_carbon_verify_bluetooth>`.
 
-.. figure:: img/96b_carbon.png
+.. figure:: img/96b_carbon.jpg
-     :width: 487px
      :align: center
      :alt: 96Boards Carbon
 

boards/arm/96b_carbon_nrf51/doc/index.rst

@@ -83,7 +83,7 @@ debugger, via the debug header labeled "BLE" on the board's
 silkscreen. The header is not populated; 0.1" male header must be
 soldered on first.
 
-.. figure:: img/96b_carbon_nrf51.png
+.. figure:: img/96b_carbon_nrf51.jpg
      :align: center
      :alt: 96Boards Carbon nRF51 Debug
 

boards/arm/96b_neonkey/doc/index.rst

@@ -10,9 +10,7 @@ Overview
 Cortex M4 CPU.
 
 .. figure:: img/96b_neonkey.jpg
-     :width: 500px
      :align: center
-     :height: 330px
      :alt: 96Boards Neonkey
 
      96Boards Neonkey

boards/arm/96b_nitrogen/doc/index.rst

@@ -9,8 +9,7 @@ Overview
 The 96Boards Nitrogen hardware provides support for the Nordic Semiconductor
 nRF52832 ARM Cortex-M4F CPU.
 
-.. figure:: img/96b_nitrogen.png
+.. figure:: img/96b_nitrogen.jpg
-     :width: 487px
      :align: center
      :alt: 96Boards Nitrogen
 

boards/arm/96b_stm32_sensor_mez/doc/index.rst

@@ -12,7 +12,7 @@ STM32F446VE Cortex M4 CPU.
 This board acts as a mezzanine platform for all 96Boards CE compliant
 boards. It can also be used as a standalone board.
 
-.. figure:: img/96b_stm32_sensor_mez.png
+.. figure:: img/96b_stm32_sensor_mez.jpg
      :align: center
      :alt: 96Boards STM32 Sensor Mezzanine
 

boards/arm/96b_wistrio/doc/96b_wistrio.rst

@@ -11,10 +11,8 @@ chipset integrating SX1276 LoRaWAN Modem, STM32L151CB-A MCU and GPS module.
 Zephyr applications use the 96b_wistrio configuration to run on these
 boards.
 
-.. figure:: img/96b-wistrio.png
+.. figure:: img/96b-wistrio.jpg
-     :width: 1000px
      :align: center
-     :height: 509px
      :alt: 96Boards WisTrio
 
      96Boards WisTrio

boards/arm/actinius_icarus/doc/index.rst

@@ -6,8 +6,7 @@ Actinius Icarus
 Overview
 ********
 
-.. figure:: img/Icarus_front.png
+.. figure:: img/Icarus_front.jpg
-     :width: 450px
      :align: center
      :alt: Icarus IoT Dev Board
 
@@ -42,8 +41,7 @@ Hardware
 
 The detailed information about the on-board hardware can be found at the `Icarus Product Website`_.
 
-.. figure:: img/Icarus_pinouts.png
+.. figure:: img/Icarus_pinouts.jpg
-     :width: 450px
      :align: center
      :alt: Icarus IoT Dev Board w/ Pinouts
 

boards/arm/actinius_icarus_bee/doc/index.rst

@@ -6,8 +6,7 @@ Actinius Icarus Bee
 Overview
 ********
 
-.. figure:: img/icarus-bee.png
+.. figure:: img/icarus-bee.jpg
-     :width: 450px
      :align: center
      :alt: Icarus Bee
 
@@ -37,15 +36,13 @@ following devices (provided directly by Nordic):
 * :abbr:`WDT (Watchdog Timer)`
 * :abbr:`IDAU (Implementation Defined Attribution Unit)`
 
-.. figure:: img/icarus-bee-external-pins.png
+.. figure:: img/icarus-bee-external-pins.jpg
-     :width: 450px
      :align: center
      :alt: Icarus Bee w/ Pinouts
 
      Icarus Bee w/ Pinouts
 
-.. figure:: img/icarus-bee-peripherals-pins.png
+.. figure:: img/icarus-bee-peripherals-pins.jpg
-     :width: 200px
      :align: center
      :alt: Icarus Bee
 

boards/arm/actinius_icarus_som/doc/index.rst

@@ -6,8 +6,7 @@ Actinius Icarus SoM
 Overview
 ********
 
-.. figure:: img/icarus-som.png
+.. figure:: img/icarus-som.jpg
-     :width: 450px
      :align: center
      :alt: Icarus SoM
 
@@ -37,15 +36,13 @@ following devices (provided directly by Nordic):
 * :abbr:`WDT (Watchdog Timer)`
 * :abbr:`IDAU (Implementation Defined Attribution Unit)`
 
-.. figure:: img/icarus-som-external-pins.png
+.. figure:: img/icarus-som-external-pins.jpg
-     :width: 450px
      :align: center
      :alt: Icarus SoM Pins
 
      Icarus SoM Pins
 
-.. figure:: img/icarus-som-peripherals-pins.png
+.. figure:: img/icarus-som-peripherals-pins.jpg
-     :width: 200px
      :align: center
      :alt: Icarus SoM
 

boards/arm/adafruit_feather_m0_basic_proto/doc/index.rst

@@ -12,7 +12,6 @@ polymer batteries, charging status indicator and user LEDs, native USB
 connector, 20 I/O pins, and a small prototyping area.
 
 .. image:: img/adafruit_feather_m0_basic_proto.jpg
-     :width: 640px
      :align: center
      :alt: Adafruit Feather M0 Basic Proto
 

boards/arm/adafruit_feather_nrf52840/doc/index.rst

@@ -26,7 +26,6 @@ nRF52840 ARM Cortex-M4F CPU and the following devices:
 * :abbr:`WDT (Watchdog Timer)`
 
 .. figure:: img/adafruit_feather_nrf52840.jpg
-     :width: 640px
      :align: center
      :alt: Adafruit Feather nRF52840 Express
 

boards/arm/adafruit_feather_stm32f405/doc/index.rst

@@ -13,7 +13,6 @@ with a lithium ion battery charger, native USB C connector, 2MB of
 external flash memory, and SD card socket.
 
 .. image:: img/adafruit_feather_stm32f405.jpg
-     :width: 640px
      :align: center
      :alt: Adafruit Feather STM32F405 Express
 

boards/arm/adafruit_itsybitsy_m4_express/doc/index.rst

@@ -10,8 +10,7 @@ The Adafruit ItsyBitsy M4 express is a small (36 mm x 18 mm) ARM development
 board with an onboard RGB LED, USB port, 2 MiB of SPI flash, and range of I/O
 broken out onto 23 GPIO pins.
 
-.. image:: img/adafruit_itsybitsy_m4_express.png
+.. image:: img/adafruit_itsybitsy_m4_express.jpg
-     :width: 500px
      :align: center
      :alt: Adafruit ItsyBitsy M4 Express
 

boards/arm/adafruit_trinket_m0/doc/index.rst

@@ -10,8 +10,7 @@ The Adafruit Trinket M0 is a tiny (27 mm x 15 mm) ARM development
 board with an onboard RGB LED, USB port, and range of I/O broken out
 onto 5 pins.
 
-.. image:: img/adafruit_trinket_m0.png
+.. image:: img/adafruit_trinket_m0.jpg
-     :width: 500px
      :align: center
      :alt: Adafruit Trinket M0
 

boards/arm/arduino_due/doc/index.rst

@@ -23,8 +23,7 @@ the processor.
 .. note::
    This configuration is not supported by Arduino.
 
-.. image:: img/arduino_due.png
+.. image:: img/arduino_due.jpg
-     :width: 500px
      :align: center
      :alt: Arduino Due
 

boards/arm/arduino_mkrzero/doc/index.rst

@@ -9,8 +9,7 @@ Overview
 The Arduino MKR Zero built with smaller MKR form factor and powered by Atmel's SAMD21 MCU.
 This board come with microSD card holder that allows you to play with music files with no extra hardware.
 
-.. image:: img/arduino_mkrzero.png
+.. image:: img/arduino_mkrzero.jpg
-     :width: 250px
      :align: center
      :alt: Arduino MKR Zero
 

boards/arm/arduino_nano_33_ble/doc/index.rst

@@ -11,8 +11,7 @@ nRF52840 ARM Cortex-M4F CPU. Arduino sells 2 variants of the board, the
 plain `BLE`_ type and the `BLE Sense`_ type. The "Sense" variant is distinguished by
 the inclusion of more sensors, but otherwise both variants are the same.
 
-.. image:: img/arduino_nano_33_ble_sense.png
+.. image:: img/arduino_nano_33_ble_sense.jpg
-     :width: 500px
      :align: center
      :alt: Arduino Nano 33 BLE (Sense variant)
 

boards/arm/arduino_nano_33_iot/doc/index.rst

@@ -9,8 +9,7 @@ Overview
 The Arduino Nano 33 IOT is a a small form factor development board with USB,
 Wifi, Bluetooth, a 6 axis IMU, and secure element.
 
-.. image:: img/nano_33_iot.png
+.. image:: img/nano_33_iot.jpg
-     :width: 500px
      :align: center
      :alt: Arduino Nano 33 IOT
 

boards/arm/arduino_nicla_sense_me/doc/index.rst

@@ -10,8 +10,7 @@ nrf52832 ARM Cortex-M4F CPU. The board houses 4 low power industrial grade senso
 that can measure rotation, acceleration, pressure, humidity, temperature, air quality
 and CO2 levels.
 
-.. figure:: arduino_nicla_sense_me.png
+.. figure:: arduino_nicla_sense_me.jpg
-   :width: 500px
    :align: center
    :alt: Arduino Nicla Sense ME
 
@@ -75,10 +74,8 @@ Connections and IOs
 
 Available pins:
 ---------------
-.. figure:: arduino_nicla_sense_me_pinout.png
+.. figure:: arduino_nicla_sense_me_pinout.jpg
-   :width: 500px
    :align: center
-   :height: 500px
    :alt: Arduino Nicla Sense ME pinout
 
    Arduino Nicla Sense ME pinout (Credit: Arduino)

boards/arm/arduino_zero/doc/index.rst

@@ -10,8 +10,7 @@ The Arduino Zero is a maker-friendly development board with
 Atmel’s Embedded Debugger (EDBG), which provides a full
 debug interface without the need for additional hardware.
 
-.. image:: img/arduino_zero.png
+.. image:: img/arduino_zero.jpg
-     :width: 500px
      :align: center
      :alt: Arduino Zero
 

boards/arm/arty/doc/index.rst

@@ -14,8 +14,7 @@ Each board is equipped with on-board JTAG for FPGA programming and debugging,
 LEDs, switches, buttons, DDR3 RAM, and QSPI flash for storing the FPGA
 bitstream.
 
-.. figure:: ./arty_a7-35.png
+.. figure:: arty_a7-35.jpg
-   :width: 500px
    :align: center
    :alt: Digilent Arty A7-35
 

boards/arm/ast1030_evb/doc/index.rst

@@ -10,8 +10,7 @@ The AST1030_EVB kit is a development platform to evaluate the
 Aspeed AST10x0 series SOCs. This board needs to be mated with
 part number AST1030.
 
-.. image:: ./ast1030_evb.png
+.. image:: ast1030_evb.jpg
-     :width: 800px
      :align: center
      :alt: AST1030 Evaluation Board
 

boards/arm/atsamd20_xpro/doc/index.rst

@@ -13,7 +13,6 @@ which provides a full debug interface without the need for additional
 hardware.
 
 .. image:: img/atsamd20_xpro.jpg
-     :width: 500px
      :align: center
      :alt: ATSAMD20-XPRO
 

boards/arm/atsamd21_xpro/doc/index.rst

@@ -12,8 +12,7 @@ microcontrollers. The kit includes Atmel’s Embedded Debugger (EDBG),
 which provides a full debug interface without the need for additional
 hardware.
 
-.. image:: img/atsamd21_xpro.png
+.. image:: img/atsamd21_xpro.jpg
-     :width: 500px
      :align: center
      :alt: ATSAMD21-XPRO
 
@@ -72,8 +71,7 @@ controllers are responsible for pin muxing, input/output, pull-up, etc.
 For mode details please refer to `SAM D21 Family Datasheet`_ and the `SAM D21
 Xplained Pro Schematic`_.
 
-.. image:: img/ATSAMD21-XPRO-pinout.png
+.. image:: img/ATSAMD21-XPRO-pinout.jpg
-     :width: 500px
      :align: center
      :alt: ATSAMD21-XPRO-pinout