#define bishopR_width 32
#define bishopR_height 32
-static char bishopR_bits[] = {
+static unsigned char bishopR_bits[] = {
0xff,0xff,0xff,0x7f,0x01,0x00,0x00,0xc0,0x01,0x00,0x00,0xc0,0x01,0x38,0x18,
0xc0,0x01,0x18,0x18,0xc0,0x02,0x18,0x18,0x60,0x02,0x18,0x58,0x60,0x02,0x18,
0x38,0x60,0x02,0xfe,0x19,0x60,0x04,0x00,0x48,0x30,0x04,0x00,0x24,0x30,0x04,