Overlay timestamps on many figures

I have 400 images like the following one:

I want to superimpose timestamps on the top left or the top right of each figure, so I will have 400 timestamps in total. Each timestamp contains hours, minutes and seconds ('HHMMSS').

For Image1 => Timestamp1 ... Image400 => Timestamp400.

I tried to use the following code:

for i = 1:400
     startDate = datenum('02-Nov-2013 13:30:06');
     endDate = datenum('02-Nov-2013 13:30:51');
     xdate = linspace(startDate,endDate,400);
     ... code to generate image
     set(gca,'XTick',xdate);
     datetick('x','HHMMSS');
end

But it became obvious that it didn't works, because I get the timestamps along an x axis, and I want a single timestamp for each image up to 400 images. Anyone has any clue how to do that?

[Jan]

The contents of the loop does not depened on i. So what should be changed in each loop? Where shoudl teh time stamps appear? In the image file or on the screen only?

[Adrian]

The content of the loop that depends on i is within the code to generate the image. I didn't want to make the code harder to read, so I didn't add it. I just wanted the timestamp on the top left, right or center of the image. It doesn't really matter.