How to get palette index

[qtbui159]

I have a 8-bit bmp file which size is 4x2 . There are two questions I want to solve.

1. How do i get this bmp's palette.(1024bytes , 256 colors)
2. How do i get the palette index of a position.

As a example , the 4x2 image like below
0x11 0x22 0x33 0x44
0x55 0x66 0x77 0x88
So the position(0,0) palette index is 0x11
the position(1,2) palette index is 0x77.

Thx.