How to read loaded image?

Hello, I am stuck right now. I want to combine gui to other m file. My m file is creating image mosaic. I have gui with pushbuttons, one of them load an image like this:

    global M im2
        [path,user_cance]=imgetfile();
       if user_cance
             msgbox(sprintf('Error'),'Error','Error');
            return
       end
       M=imread(path);
       M=im2double(M); 
       im2=M; 
    axes(handles.axes1);
    imshow(M);

And i dont know how to link this loaded image in mfile, where this loaded image becomes a photo mosaic. Now, i just using default picture like this

   M = imread('mandrill.png');

in my m file, and everyting is working, but i need to do smth that my m file will start working with loaded picture in gui.