Why the FOR LOOP take a part of the data set?

I created a for loop for the data set that include 748 images. but when I did run the out put only 40 images.

Please I need your help to solve this problem.

Thank you in advance

Here is the code

cd G:\marshals_iraque\bdados\INDEX\VNDWI\MOD09A1_HA;
F_read=dir('*.tif');
for i=1:length(F_read)
  vndwi_cn{i}= F_read(i).name;    
  vndwi_cn{i} = imread(vndwi_cn{i});
  vndwi_cn{i}(vndwi_cn{i}<0)=NaN;
  vndwi_cn{i}(vndwi_cn{i}==0)=NaN;
  vndwi_cn_Avg{i}=nanmean (vndwi_cn{i}(:));
end

[KSSV]

What is value of length(F_read)?

[reyadh Albarakat]

F_read is 748

[dpb]

Doesn't look likely...show us the actual command and result from the command line that makes you think that is so...or, there must've been an error that aborted the loop prematurely; show us any other output including all error messages in context and in toto...