For example:
for K = 1 : 15
filename = sprintf('Output_%02d.jpg', K);
surf( rand(5,5) ); %some plot
drawnow();
saveas(gca, filename)
end
That is, you can compute the filename that you pass to saveas(). In the above example, %02d means to output as an integer of at least two digits using leading 0's if needed to make two digits -- so 01 then 02 then 03 ... 09 then 10 then 11 and so on.
