text to mif conversion

i have this full program,its work.but then when i want to change the spesific size,it have the error.

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name = 'image';

img = imread(strcat(name,'.gif'));

g = im2double(img);

g = g/max(max(g));

rgb = cat(3,g,g,g);

imshow(rgb);

out = ones(480,640);

out(10+(1:460),90+(1:460)) = img;

imshow(out);

x = out';

x = uint8(x(:));

n = length(x);

y = reshape(x,8,n/8)';

z = y(:,8);

for i=1:7

z = bitor(z,bitshift(y(:,i),8-i));

end

m = 0;

n = 1;

v = z(1);

for i=2:length(z)

if (z(i)~=v)

m = m + 1;

value(m) = v;

runlen(m) = n;

n = 1;

v = z(i);

else

n = n + 1;

end

end

m = m + 1;

value(m) = v;

runlen(m) = n;

fprintf('total runs %d\n',sum(runlen));

fprintf('number of runs %d\n',length(runlen));

nz = length(find(value==0));

nf = length(find(value==255));

fprintf('zeros %d all ones %d\n',nz,nf);

dfv = 255;

fid = fopen(strcat(name,'.mif'),'w');

str = 'WIDTH=8;\nDEPTH=38400;\n\nADDRESS_RADIX=HEX;\nDATA_RADIX=HEX;\n\n';

fprintf(fid,str);

str = 'CONTENT BEGIN\n [0000..%04X] : %X;\n';

fprintf(fid,str,sum(runlen)-1,dfv);

n = 0;

for k=1:length(runlen)

if (runlen(k)==1)

str = sprintf(' %04X : %X;\n', n, value(k));

else

str = sprintf(' [%04X..%04X] : %X;\n', n, n+runlen(k)-1, value(k));

end

if (value(k) ~= dfv)

fprintf(fid,str);

end

n = n + runlen(k);

end

fprintf(fid,'END;\n');

fclose(fid);

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can you show me how to make the image 16bits width and 4096bits depth.

which part should i alter?

thank you.