Why i'm getting imcrop error

NotYet = false;
C = webcamlist;
cam=webcam(C{3});
preview(cam);
while ~NotYet
    tic;pause(0.10);toc;
    I = snapshot(cam);
    faceDetect = vision.CascadeObjectDetector();
    bbox=step(faceDetect,I);
    if ~isempty(bbox)
        NotYet = true;
        break;
    end
end
closepreview;
clear('cam');
face = imcrop(I,bbox);
imwrite(face, 'face.png');

how to avoid these error while presenting to external

Error in imshow (line 222)
      images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});
Error in imcrop>parseInputs (line 252)
            imshow(a,cm);
Error in imcrop (line 93)
[x,y,a,cm,spatial_rect,h_image,placement_cancelled] =
parseInputs(varargin{:});
Error in DetectFaceandEyes (line 19)
face = imcrop(I,bbox);

[John D'Errico]

What error do you get? Show the COMPLETE error message, rather than force others to try to recreate it.

[Ankit Singh]

Error in imshow (line 222)
      images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});

Error in imcrop>parseInputs (line 252)
            imshow(a,cm);

Error in imcrop (line 93)
[x,y,a,cm,spatial_rect,h_image,placement_cancelled] =
parseInputs(varargin{:});

Error in DetectFaceandEyes (line 19)
face = imcrop(I,bbox);

Error in Trianing (line 10)
DetectFaceandEyes;

My Whole Code

Above link have my Whole Code

Thanks For your reply

[Image Analyst]

What is:

bbox
size(I)

Don't use semicolons. Tell us what that shows in the command window. Oh, and read this.

[Ankit Singh]

bbox =

   564   165   265   265

ans =

         720        1280           3

sometimes it works and sometimes doesn't

software shows warning or error without semicolons