reading the images

I ahve athe code

im = imread('1.tif');
for i = 2:1000
 im = imadd(im,imread(sprintf('%d.tif',i)));
end
im = im/1000;
imshow(im,[]);

which i got from net,please tell how to read my images and get result,

i have my 200 images of same size in image folder,i tried replacing in imread ,but i get error ,plz help

[Image Analyst]

You forgot to copy and past the error and you haven't read this yet: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer