Why does using pygame.transform.rotate() change the size of my image instead of rotating it?

Question

I'm importing an image and trying to get it to "face" the mouse as a player character would. I've gotten the movement to work, including scaling to length with a vector, so diagonal movement isn't faster than horizontal/vertical movement but moving the mouse just changes the size of the image for some reason, it doesn't rotate it.

I'm not sure what I could be doing wrong, to cause pygame.transform.rotate to instead scale the image, so I'm just putting the whole code here because I have no idea what I'm doing wrong. I've tried about 4 different ways of getting it to rotate from various places on this website, and they all seems to make the image scale in various ways, rather than rotate.

import pygame
import math
from pygame.locals import (
    RLEACCEL,
    K_w,
    K_a,
    K_s,
    K_d,
    K_ESCAPE,
    KEYDOWN,
    KEYUP,
    QUIT
)

pygame.mixer.init()

pygame.init()

clock = pygame.time.Clock()

player_class = "default"

screen_width = 1920
screen_height = 1080
screen = pygame.display.set_mode((screen_width,screen_height))

#player character class speed. Move into player class info when ready
player_speed = 5
player_spawn = [20.0, 20.0]


class Player(pygame.sprite.Sprite):

    def __init__(self, player_spawn):
        super(Player, self).__init__()
        self.image = pygame.image.load(f"{player_class}.png").convert()
        self.orig_image = self.image
        self.rect = self.image.get_rect(center=player_spawn)


    def update(self, pressed_keys):
        global player_speed

        move_up = 0
        move_down = 0
        move_left = 0
        move_right = 0
        if pressed_keys[K_w]:
            move_up = 1
        if pressed_keys[K_a]:
            move_left = 1
        if pressed_keys[K_s]:
            move_down = 1
        if pressed_keys[K_d]:
            move_right = 1

        player_vector = pygame.math.Vector2(
            move_right - move_left,
            move_down - move_up
        )

        if player_vector.x != 0 or player_vector.y != 0:
            player_vector.scale_to_length(player_speed)
            self.rect.move_ip(player_vector.x, player_vector.y)

        direction = pygame.math.Vector2(pygame.mouse.get_pos()) - self.rect.center
        radius, angle = direction.as_polar()
        self.image = pygame.transform.rotate(self.orig_image, angle)
        self.rect = self.image.get_rect(center=self.rect.center)


        if self.rect.left < 0:
            self.rect.left = 0
        if self.rect.right > screen_width:
            self.rect.right = screen_width
        if self.rect.top < 0:
            self.rect.top = 0
        if self.rect.bottom > screen_height:
            self.rect.bottom = screen_height


player = Player(player_spawn)

all_sprites = pygame.sprite.Group()
all_sprites.add(player)

running = True

while running:
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            if event.key == K_ESCAPE:
                running = False

        elif event.type == QUIT:
            running = False

    pressed_keys = pygame.key.get_pressed()
    player.update(pressed_keys)

    screen.fill((135, 206, 250))

    for entity in all_sprites:
        screen.blit(entity.image, entity.rect)

    pygame.display.flip()

    clock.tick(60)