how to create a white image?

I would like to create a NxM white image. But how to put color vectors [256 256 256] into a 2D array?

Answer 1

[Image Analyst]

Try this to create a grayscale image:

whiteImage = 255 * ones(N, M, 'uint8');
imshow(whiteImage);

To create an RGB image, try this:

whiteImage = 255 * ones(480, 640, 3, 'uint8');
imshow(whiteImage);

Answer 2

[John BG]

max allowe [255 255 255] I repeat, the range is [0 255], 256 values.