Multi level decomposition of image for image compression using ANN

I am working on image compression using ANN. I have splitted the image into 16 parts and each part is given as input to ANN for image compression. My approach is

a=imread('image.png');

x=imresize(a,[64 64]);

xn=mat2gray(x);

[r c]=size(xn);

x1=xn(1:r/4,1:c/4);

x2=xn(1:r/4,c/4+1:c/2);

x3=xn(1:r/4,c/2+1:(3/4)*c);

x4=xn(1:r/4,(3/4)*c+1:c);

x5=xn(r/4+1:r/2,1:c/4);

x6=xn((r/4)+1:r/2,c/4+1:(1/2)*c);

x7=xn(r/4+1:r/2,(1/2)*c+1:(3/4)*c);

x8=xn(r/4+1:r/2,(3/4)*c+1:c);

x9=xn(r/2+1:3/4*r,1:c/4);

x10=xn(r/2+1:3/4*r,c/4+1:(1/2)*c);

x11=xn(r/2+1:3/4*r,(1/2)*c+1:(3/4)*c);

x12=xn(r/2+1:3/4*r,(3/4)*c+1:c);

x13=xn(3*r/4+1:r,1:c/4);

x14=xn(3*r/4+1:r,c/4+1:c/2);

x15=xn(3*r/4+1:r,c/2+1:(3/4)*c);

x16=xn(3*r/4+1:r,(3/4)*c+1:c);

Then I created two ANN s for each subimage for compression and decompression of the image using the command feedforwardnet. But I found the following errors.I have done 4-level and 9-level decomposition image compression using the same method and it worked. How to overcome the errors? ??? Error using ==> trainlm at 109 Input data size does not match net.inputs{1}.size.

Error in ==> network.train at 107 [net,tr] = feval(net.trainFcn,net,X,T,Xi,Ai,EW,net.trainParam);

Error in ==> test_21_11 at 136 net_s5d=train(net_s5d,pds5,tds5,0,1,0.001);