You can use the handles structure with the guidata function to store/save user data to the structure. Try something like this
function pushbutton1_Callback(hObject, eventdata, handles)
% call your script
[im, hdr,old, datafile, hdrfile]= imgImport;
% assign the user data to the structure
handles.im = im;
handles.hdr = hdr;
% save the data
guidata(hObject,handles);
Now in your other button callback, just access the data directly from the handles structure:
function pushbutton2_Callback(hObject, eventdata, handles)
[imgVIS, imgSWIR, rect,img,rowend, rowstart, colend, colstart] = …
cropping(handles.im, handles.hdr);
Try the above and see if that does what you wish.
