plot an image using pulsating voltage

i have a data i.e voltage values which are varying at a faster rate ,

how to show them as a grayscale image with 32 by 32 size( there should be image with 32 by 32 pixels )

and what should be the range of the voltage values ?

[amogha]

a = csvread('lt1.csv');

B = rescale(a,0,255);

V=B

N = numel(V) ;

M = NaN(ceil(sqrt(N))) ;

M(1:N) = V ;