[fname,pname]=uigetfile('*.*','Nacitanie obrazku');
filename=strcat(pname,fname);
[X,map]=imread(filename);
KX=size(X);
Kmap=size(map);

%Vytvorenie Gaussovského šumu
for i=1:KX(1,1)
    for j=1:KX(1,2)
        pixel=X(i,j);
        Y(i,j)=round(pixel+(pixel*(rand-0.5)));
    end
end
figure, imshow(Y);