Loading either one or multiple images GUI

I want to load multiple images in Matlab GUI. Algorithm below:

 % --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
[filename path] = uigetfile('*.jpg','*.png','Chose files to 
load','MultiSelect','on');

 if isequal(filename,0) || isequal(path,0) 
return
end

 if iscell(filename)
img = cell(size(filename));
for ii = 1:numel(filename)
  img{ii} = imread(fullfile(path,filename{ii}));
end
else
img{1} = imread(fullfile(path,filename));
end

 filename = strcat(path,filename);
fullpathname = strcat(path, filename);
set(handles.edit1,'String', fullpathname);
fileID = fopen(strcat(path, filename), 'r');

I also need the directory of an image or images to bee seen text box, but it gives me subsequent error:

 Error using imread>parse_inputs (line 457)
The file name or URL argument must be a string.

 Error in imread (line 316)
[filename, fmt_s, extraArgs] = parse_inputs(varargin{:});

 Error in untitled>pushbutton1_Callback (line 112)
im = rgb2gray(imread(filename));

 Error in gui_mainfcn (line 95)
    feval(varargin{:});

 Error in untitled (line 42)
gui_mainfcn(gui_State, varargin{:});

 Error in 
@(hObject,eventdata)
untitled('pushbutton1_Callback',hObject,eventdata,guidata(hObject))

Could you please give me a hint, so I could make it functional?