Issues with changing images for players in Pygame using classes

Question

I have run into issues with my generic Player class for my character in a simple RPG game I am developing.

I am trying to make it so that when I press the 'left' key to move left the character not only goes left but also changes its image to look like it is running left by my current code (attached below) keeps crashing with various errors.

import pygame
from pygame import *

class Player(pygame.sprite.Sprite):
    image_normal = pygame.image.load('images/player/normal.png').convert()
    image_left = pygame.image.load('images/player/left.png').convert()
    image_right = pygame.image.load('images/player/right.png').convert()

    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = image_normal
        self.rect = self.image.get_rect()

    def update(self, UP, DOWN, LEFT, RIGHT, WIN_WIDTH, WIN_HEIGHT):
        """Move the player."""
        if UP == True:
            if self.rect.y > 0:
                self.rect.y -= 5
        if DOWN == True:
            if self.rect.bottom < WIN_HEIGHT:
                self.rect.y += 5
        if LEFT == True:
            self.image = image_left
            if self.rect.x > 0:
                self.rect.x -= 5
        if RIGHT == True:
            self.image = image_right
            if self.rect.right < WIN_WIDTH:
                self.rect.x += 5
        else:
            self.image = image_normal

The Error is:

Traceback (most recent call last):
  File "D:\StoD\main.py", line 11, in <module>
    import player
  File "D:\StoD\player.py", line 15, in <module>
    class Player(pygame.sprite.Sprite):
  File "D:\StoD\player.py", line 16, in Player
    image_normal = pygame.image.load('images/player/normal.png').convert() 
pygame.error: cannot convert without pygame.display initialized