How to run m.file in gui?

Hello! I loaded an image and displayed it in the axis box. What I'm trying to do now is to use a function I created and saved as a separate file to enhance the image, which I've just displayed.

So this is my image load code:

% --- Executes on button press in Image_load.
function Image_load_Callback(hObject, eventdata, handles)
% hObject    handle to Image_load (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
%----------> here we load image

global im im2
[path,user_cance]=imgetfile();
if user_cance
    msgbox(sprintf('Error'),'Error','Error');
    return
end
im=imread(path);
im=im2double(im); %converts to double
im2=im; %for backup process :)
axes(handles.axes1);
imshow(im);

The function created is called "enhancement". And this is where I'm stuck:

% --- Executes on button press in Enhance.
function Enhance_Callback(hObject, eventdata, handles)
% hObject    handle to Enhance (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% get the image data

B=enhancement(im);
axes(handles.axes1);
imshow(B);