80386 machine code, IBM PC DOS, 38 bytes

hex:

B0 13 CD 10 68 00 A0 1F 66 C7 06 00 00 28 2C 24
00 66 C7 06 40 01 2C 30 34 00 66 C7 06 80 02 24
34 20 00 CD 16 C3

asm:

mov al,13h
int 10h ; initialize vga 13h mode (320x200x256 colors)
push 0a000h
pop ds ; set ds to video buffer
mov dword ptr ds:0, 242c28h ; print 3 pixels
mov dword ptr ds:320, 34302ch ; print 3 pixels
mov dword ptr ds:640, 203424h ; print 3 pixels
int 16h ; wait for any keypress
ret # exit to os

scaled output from dosbox: