diff --git a/image.h b/image.h
index a01fc5d..4d0e65d 100644
--- a/image.h
+++ b/image.h
@@ -17,7 +17,7 @@
 #include "svgrgb565.h"
 
 //27*11 = 297 * 2B = 594B
-static uint16_t cannon_sprite[297] PROGMEM = {
+static const uint16_t cannon_sprite[297] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,GREEN,GREEN,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,GREEN,GREEN,GREEN,GREEN,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,GREEN,GREEN,GREEN,GREEN,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
@@ -32,7 +32,7 @@ static uint16_t cannon_sprite[297] PROGMEM = {
 };
 
 //27*11 = 297 * 2B = 594B
-static uint16_t cannon_sprite_2[297] PROGMEM = {
+static const uint16_t cannon_sprite_2[297] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,BLACK,GREEN,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,
@@ -47,7 +47,7 @@ static uint16_t cannon_sprite_2[297] PROGMEM = {
 };
 
 //27*11 = 297 * 2B = 594B
-static uint16_t cannon_sprite_3[297] PROGMEM = {
+static const uint16_t cannon_sprite_3[297] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,
     BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,BLACK,
     BLACK,BLACK,GREEN,BLACK,GREEN,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,BLACK,GREEN,BLACK,BLACK,GREEN,BLACK,BLACK,BLACK,GREEN,
@@ -62,7 +62,7 @@ static uint16_t cannon_sprite_3[297] PROGMEM = {
 };
 
 //9*8 = 72 * 2B = 144B
-static uint16_t heart_sprite[72] PROGMEM = {
+static const uint16_t heart_sprite[72] PROGMEM = {
     BLACK,RED,RED,BLACK,BLACK,BLACK,RED,RED,BLACK,
     RED,RED,RED,RED,BLACK,RED,RED,RED,RED,
     RED,RED,RED,RED,RED,RED,RED,WHITE,RED,
@@ -74,7 +74,7 @@ static uint16_t heart_sprite[72] PROGMEM = {
 };
 
 //16x14
-static uint16_t astro_sprite[] PROGMEM = {
+static const uint16_t astro_sprite[] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,RED,RED,RED,RED,RED,RED,DARK_RED,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,RED,RED,RED,RED,RED,RED,DARK_RED,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,RED,RED,RED,RED,RED,RED,RED,RED,RED,RED,DARK_RED,BLACK,BLACK,
@@ -92,7 +92,7 @@ static uint16_t astro_sprite[] PROGMEM = {
 };
 
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_1A[] PROGMEM = {
+static const uint16_t monster_sprite_1A[] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
@@ -111,7 +111,7 @@ static uint16_t monster_sprite_1A[] PROGMEM = {
     BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_1B[] PROGMEM = {
+static const uint16_t monster_sprite_1B[] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
@@ -130,7 +130,7 @@ static uint16_t monster_sprite_1B[] PROGMEM = {
     BLACK,BLACK,WHITE,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,WHITE,BLACK,BLACK,BLACK
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_2A[416] PROGMEM = {
+static const uint16_t monster_sprite_2A[416] PROGMEM = {
     BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,
@@ -149,7 +149,7 @@ static uint16_t monster_sprite_2A[416] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_2B[416] PROGMEM = {
+static const uint16_t monster_sprite_2B[416] PROGMEM = {
     BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,
     BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,
@@ -168,7 +168,7 @@ static uint16_t monster_sprite_2B[416] PROGMEM = {
     BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_3A[] PROGMEM = {
+static const uint16_t monster_sprite_3A[] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,
@@ -187,7 +187,7 @@ static uint16_t monster_sprite_3A[] PROGMEM = {
     BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK,BLACK,BLACK
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_3B[] PROGMEM = {
+static const uint16_t monster_sprite_3B[] PROGMEM = {
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,
     BLACK,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,WHITE,BLACK,BLACK,
@@ -206,7 +206,7 @@ static uint16_t monster_sprite_3B[] PROGMEM = {
     WHITE,WHITE,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,BLACK,WHITE,WHITE,BLACK
 };
 //13x8 = 104 * 2B = 208B
-static uint16_t monster_sprite_exp[416] PROGMEM = {
+static const uint16_t monster_sprite_exp[416] PROGMEM = {
     BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,
     BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,BLACK,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,
     BLACK,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,WHITE,BLACK,BLACK,WHITE,BLACK,BLACK,
@@ -226,7 +226,7 @@ static uint16_t monster_sprite_exp[416] PROGMEM = {
 };
 
 //4x9
-static uint16_t triangle_sprite[28] PROGMEM = {
+static const uint16_t triangle_sprite[28] PROGMEM = {
     BLUE,BLACK,BLACK,BLACK,
     BLUE,BLUE,BLACK,BLACK,
     BLUE,BLUE,BLUE,BLACK,
diff --git a/lcd/lcd.c b/lcd/lcd.c
index c418b45..01d6e90 100644
--- a/lcd/lcd.c
+++ b/lcd/lcd.c
@@ -117,7 +117,7 @@ void set_frame_rate_hz(uint8_t f) {
     write_data(rtna);
 }
 
-void fill_image_pgm(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col) {
+void fill_image_pgm(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col) {
     write_cmd(COLUMN_ADDRESS_SET);
     write_data16(x);
     write_data16(x+width);
@@ -162,7 +162,7 @@ void fill_image_pgm(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uin
     }
 }
 
-void fill_image_pgm_2b(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col) {
+void fill_image_pgm_2b(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col) {
     write_cmd(COLUMN_ADDRESS_SET);
     write_data16(x);
     write_data16(x+width-1);
@@ -213,7 +213,7 @@ void fill_image_pgm_2b(uint16_t x, uint16_t y, uint16_t width, uint16_t height,
     }
 }
 
-void fill_image(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col) {
+void fill_image(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col) {
     write_cmd(COLUMN_ADDRESS_SET);
     write_data16(x);
     write_data16(x+width);
diff --git a/lcd/lcd.h b/lcd/lcd.h
index 4ffb7de..9d719ef 100644
--- a/lcd/lcd.h
+++ b/lcd/lcd.h
@@ -47,9 +47,9 @@ void display_string(char *str);
 void display_string_xy(char *str, uint16_t x, uint16_t y);
 void display_string_xy_col(char *str, uint16_t x, uint16_t y, uint16_t col);
 void display_register(uint8_t reg);
-void fill_image(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col);
-void fill_image_pgm(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col);
-void fill_image_pgm_2b(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint16_t *col);
+void fill_image(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col);
+void fill_image_pgm(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col);
+void fill_image_pgm_2b(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint16_t *col);
 void display_uint8(uint8_t i);
 void display_uint16(uint16_t i);
 void display_uint32(uint32_t i);