how ot code gui scrollbar ?

I'd use the scrollbar built in to a listbox. A listbox is so much more user friendly than a scroll bar because you can see the name and pick the image directly from the list. You can load a listbox like this:

%=====================================================================
% Load up the listbox with image files in folder handles.ImageFolder
function handles=LoadImageList(handles)        
  ListOfImageNames = {};
  folder = handles.ImageFolder;
  if ~isempty(handles.ImageFolder) 
    if exist(folder,'dir') == false
      msgboxw(['Folder ' folder ' does not exist.']);
      return;
    end
  else
    msgboxw('No folder specified as input for function LoadImageList.');
    return;
  end
  % If it gets to here, the folder is good.
  ImageFiles = dir([handles.ImageFolder '/*.*']);
  for Index = 1:length(ImageFiles)
    baseFileName = ImageFiles(Index).name;
    [folder, name, extension] = fileparts(baseFileName);
    extension = upper(extension);
    switch lower(extension)
    case {'.png', '.bmp', '.jpg', '.tif', '.avi'}
      % Allow only PNG, TIF, JPG, or BMP images
      ListOfImageNames = [ListOfImageNames baseFileName];
    otherwise
    end
  end
  set(handles.lstImageList,'string',ListOfImageNames);
    return