Why imshow is not working?

I try to read a txt with rows and columns as many as dicom images are and align the images in accordance to x,y values that are written on this txt.

Finally, I try to imshow them but although no error occurs, still the RUN process stops and nothing happens. Can you explain why?

Here is the code I use

filePatternu = fullfile(destinationFolder, '*.dcm');
allFiles = dir(filePatternu);

for k= 2: 1: length(allFiles)
   baseFileName = allFiles(k).name; % e.g. "1.png"
   fullFileName = fullfile(destinationFolder, baseFileName); 
   I = dicomread(fullFileName); % img respresents input image.
   pause(2)
   [x, y] = textread('imgpositions.txt', '%f , %f');
   figure
   imshow(I, [x y])
   drawnow;
end

[Guillaume]

Nothing is shown at all? I would expect your axis to be filled with all black or all white at least.

Note that if x and y are supposed to be image coordinates, then that is certainly not how to do it. Your x and y will be interpreted as intensity range by imshow.

Note that because you call figure inside the loop, each image will be displayed in its own figure. So I would expect several figures to pop up. If no figure pops up then that's because no file was found.

[Siyu Guo]

I think the first thing to do is to determine where the execution is suspended. Try add some interactions by "input('press any key...', 's');" after statements in the loop to investigate the bottleneck.

[John D'Errico]

I'm not sure what you think it does. But from the help for imshow, we see:

imshow(I,[LOW HIGH]) displays the grayscale image I, specifying the display
  range for I in [LOW HIGH]. The value LOW (and any value less than LOW)
  displays as black, the value HIGH (and any value greater than HIGH) displays
  as white. Values in between are displayed as intermediate shades of gray,
  using the default number of gray levels.

the form

imshow(I,[x,y])

is NOT designed to montage a set of images.

You cannot just make up a meaning for the inputs to a function and hope that it will understand your purpose. So if you call imshow as you did, it will try to display ONE image, with a pixel value of x shown as black, and y as white.