Projective Transforms from an image to another image

[someone222]

Hi,
I am quite new to Matlab. I am trying to do a projective transform from one image to another.

I could load the image
I = imread('img1.pgm');

Then created the projective matrix
h= [ a b c; d e f; g h i];
^ this is a projective transform matrix

Then created the transform
tform = maketform('projective',h);

Now what should I do next? I tried
J = imtransform(B,tform)

But I ended up with just
J = [0 0 ; 0 0]

Even though I was pretty big (800*600)

What am I doing wrong?

Thank you very much in advance