how to solve imread() issues?

Answer 1

[Walter Roberson]

That is not an imread() issue. That is imshow() telling you that somehow you have deleted the figure you were attempting to display into.

If your code has any "close all" calls in it, then remove those calls.

[Image Analyst]

imshow() does not require any figure or axes to be existing in advance. It will create them if there are none:

close all force; % Close down all existing figures.
image2 = imread('moon.tif');
% imshow will automatically create a figure, 
% with an axes on it, and display image2 in the axes.
imshow(image2, []);

[Walter Roberson]

However if the user closes the figure between the time it is created and the time everything is set up properly then you could get this message.

Answer 2

[Image Analyst]

You may have overwritten imshow() with your own version, though it's doubtful.

imshow() will create a figure and axes if it needs to.

Even if you had deleted image2, you would have gotten a different error:

delete image2;
imshow(image2, []); 

Warning: File 'image2' not found. 
> In test (line 2)

or

clear('image2');
imshow(image2, []); 

Undefined function or variable 'image2'.
Error in test (line 2)
imshow(image2, []);

Please attach Q1.m, or at least the first 29 lines of it, so we can see what's wrong.