How to show multiple figures in MATLAB

I have 4 color images , and I'm used subplot to show these images in one figure, then I converted all to grayscale images and I showed images by using another subplot, and then I found the histogram for all grayscale images also I used another subplot to show these histograms, but when I implement the program the last subplot (I mean histograms) show only, here my question how I can show all figures ( all subplot ) One follows the other :

c1 , c2 , c3 , c4   .... the names of the four color images
g1 , g2 , g3 , g4   .... the names of the four grayscale images
h1 , h2 , h3 , h4   .... the names of the four histograms

subplot(2,2,1),imshow(c1,[]),title('c1');
subplot(2,2,2),imshow(c2,[]),title('c2');
subplot(2,2,3),imshow(c3,[]),title('c3');
subplot(2,2,4),imshow(c4,[]),title('c4');

subplot(2,2,1),imshow(g1,[]),title('g1');
subplot(2,2,2),imshow(g2,[]),title('g2');
subplot(2,2,3),imshow(g3,[]),title('g3');
subplot(2,2,4),imshow(g4,[]),title('g4');

subplot(2,2,1),imshow(h1,[]),title('h1');
subplot(2,2,2),imshow(h2,[]),title('h2');
subplot(2,2,3),imshow(h3,[]),title('h3');
subplot(2,2,4),imshow(h4,[]),title('h4');

[Madhu Govindarajan]

Looks like you will need 3 2x2 plots in a row so why not try calling them a 6x2 image. However, the size of the plots might be too small given that there are going to be so many images.