how to convert bmp image to specific size vector ?

I have dataset conains 1000 of bmp images. I need to prepare training matrix for the neural network so I'm trying to convert images to vectors with the same size, then I will append these vectors in one matrix. my problem : I'm getting different vectors sizes for each different image ! I attached example of 2 bmp image swill produce different size vectors. my code :

image = imread('sample0.bmp');
   number=im2double(image);   
   number = number';       
   vector1=number(:);  

     image2 = imread('sample1.bmp');
     number=im2double(image1);   
     number = number';       
     vector2=number(:);

Answer 1

[Image Analyst]

imresize() immediately springs to mind. Why not use that?