It is easier than ever to display a jpeg image using Pimoroni's version of micropython https://github.com/pimoroni/pimoroni-pico
The code is easy-peasy:
# Display an image on a pimoroni Pico Display
# -Scottie 2022
from picographics import PicoGraphics, DISPLAY_PICO_DISPLAY, PEN_RGB332
import jpegdec
# PEN_RGB332 is an 8 bit, fixed 256 colour palette which conserves your RAM.
# Try switching the pen_type to PEN_RGB565 (16 bit, 65K colour) and see the difference!
display = PicoGraphics(DISPLAY_PICO_DISPLAY, pen_type=PEN_RGB332, rotate=0)
# Create a new JPEG decoder for our PicoGraphics
j = jpegdec.JPEG(display)
# Open the JPEG file
j.open_file("e14scottie.jpg")
# Decode the JPEG
j.decode(0, 0, jpegdec.JPEG_SCALE_FULL)
# Display the result
display.update()
And, ta-da 
The image I used for reference:
The Image is 240x120 pixels and in jpeg format has a file size of 16 KB.
Pimoroni have done a number of update to the Picographics python module in the last year. This image was displayed in a 332RGB color format. I am totally impressed how well the colors rendered with such a limited color depth.
