rom generating code problem

what is a massive rom..

my rom contains data of an image's pixels

here is its code

entity memo_rom is

generic (pixel : integer := 9 ; img_width_cols : integer := 320; img_height_rows : integer := 240; addr_size : integer := 20);

port(clk : in std_logic;

en : in std_logic;

addr : in std_logic_vector(addr_size-1 downto 0);

data_out: out std_logic_vector(pixel-1 downto 0)

);

end entity;

architecture behavioral of memo_rom is

type ROM_Array is array ((img_width_cols*img_height_rows)-1 downto 0) of std_logic_vector (pixel-1 downto 0);

--image size 240*320 (row*col) pixels

constant rom_data: ROM_Array := (

0 =>"000000000",

1 =>"000000000",

2 =>"000000000",

3 =>"000000000",

4 =>"000010111",

5 =>"010100011",

6 =>"010010001",

......

......

......

76797 =>"000000000",

76798 =>"000000000",

76799 =>"000000000",

OTHERS => "ZZZZZZZZZ"

) ;

begin

data_out <= rom_data(conv_integer(addr)) when(en = '1') else "ZZZZZZZZZ";

end behavioral;

i've changed the "ZZ..ZZ" to "00..00" but nothing changed

there is nothing in my code that reaches this value 971456

Thanks alot,

Niveen