moving image with blit

[nilamo]

while done == False:
    screen.fill(WHITE)
# ...snip...
    screen.blit(bg_image,[45,0])
    screen.blit(player1_img, [0, 545])
    screen.blit(player2_img, [0, 565])
# ...snip...

Every iteration, you draw the players at the same spot, right before checking for events. If you want them to move, you need to track their current location somewhere (and probably initialize that location to (0, 545)), and update it when you want them to move.