mpd-notify.sh

#!/bin/bash
# Send notification with album art (if found) when mpd plays a new song, depends on libnotify

readonly MUSIC_DIR="${HOME}/Music"

while true; do
  SONG_PATH="$(mpc --format '%file%' current --wait)"
  
  if [[ ! -z "$SONG_PATH" ]]; then # check if song is being played
    SONG_DIR="$(dirname "${SONG_PATH}")"
    # Current implementation for covers, search recursevly from the current song directory
    # if not found then prints the default music folder icon
    ALBUM_ART_PATH="$(find "${MUSIC_DIR}"/"${SONG_DIR}" -type f -iname '*cover*.jpg' -o -iname '*book*.jpg' | head -n 1)"
    # ALBUM_ART_PATH="${MUSIC_DIR}/${SONG_DIR}/cover.jpg"
    SONG_INFO="$(mpc --format '%title%\n%artist%\n%album%' current)"
    if [[ -f "${ALBUM_ART_PATH}" ]]; then # cover exist
      notify-send -i "${ALBUM_ART_PATH}" "Now Playing" "${SONG_INFO}"
    else
      notify-send -i folder-music "Now Playing" "${SONG_INFO}"
    fi
  fi
done

Adjusted format output to my liking