why 512 * 512 png image is executing properly the DWT code while 512*512 mbp image is not

close all; clear all;
map=gray(256);
% get db filter length 6
[Lo_D,Hi_D,Lo_R,Hi_R] = wfilters('bior5.5');

imData=imread('lena_2.bmp');% *WORKING WITH BARBARA.PNG*
figure(1);
imshow(imData);

% first dwt
[N, M]=size(imData);
% dwt in row
dwt_row_image=zeros(N, M);
tmpData=zeros(1, M);
for i=1:N
    tmpData(1, 1:M)=imData(i, 1:M);
    tmpData(1, 1:M)=dwt(tmpData, Lo_R);
    dwt_row_image(i, 1:M)=tmpData(1, 1:M);
end

figure(2);
imshow(dwt_row_image, map);

% dwt in column
tmpData=zeros(1, N);
dwt1_imData=zeros(N, M);
for i=1:M
    tmpData(1, 1:N)=dwt_row_image(1:N, i)';
    tmpData(1, 1:N)=dwt(tmpData, Lo_R);
    dwt1_imData(1:N, i)=tmpData(1, 1:N)';
end

figure(3);
imshow(dwt1_imData, map);