Need help with color transparency

Hello, i am trying to make the white pixels in my image to be transparent and i don't know what to put as parameter.

const uint8_t witchData[] = {
    16, 16, 
    1, 0, 
    1, 
    0x77, //transparent color ?
    1, 
    0x77, 0x77,0x77, 0x77,0x77, 0x77,0x77, 0x77,
    0x77, 0x77,0x77, 0x77,0x00, 0x00,0x77, 0x77,
    0x77, 0x77,0x77, 0x00,0x00, 0x11,0x07, 0x77,
    0x77, 0x77,0x00, 0x00,0x01, 0x11,0x07, 0x77,
    0x77, 0x70,0x00, 0x00,0x11, 0x10,0x07, 0x77,
    0x70, 0x00,0x00, 0x00,0x11, 0x07,0x07, 0x77,
    0x77, 0x01,0x1f, 0x10,0x01, 0x07,0x77, 0x77,
    0x77, 0x70,0xff, 0xf1,0x00, 0x07,0x77, 0x77,
    0x77, 0x70,0x3f, 0xf3,0x10, 0x00,0x07, 0x77,
    0x77, 0x70,0xff, 0xff,0xf1, 0x07,0x77, 0x77,
    0x77, 0x77,0x00, 0x11,0x11, 0x07,0x77, 0x77,
    0x77, 0x77,0x00, 0xdd,0x11, 0x77,0x77, 0x77,
    0x77, 0x70,0x00, 0x0d,0xd1, 0x77,0x99, 0x77,
    0x77, 0x55,0x50, 0x0d,0xd1, 0x55,0x99, 0x97,
    0x77, 0x77,0x77, 0x00,0x00, 0x07,0x79, 0x97,
    0x77, 0x77,0x77, 0x70,0x70, 0x77,0x77, 0x79
    };