혹시 절대 경로 말고 다른 방밥으로 성공 하셨는지요...? 저도 같은 문제로 고민중인데....

아직도 헤매고 있어서 ㅠㅠ

EXTERNAL_CONTENT_URI 사용하지 않았습니다.
gridview 진입시 선택된 폴더의 path 를 넘겨 받아  폴더내의 이미지 list 의 정보를 구하여 gridview 를 구현 하였습니다.
수정한 코드 입니다.
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.gridview);
            //init_phone_image_grid();
      Bundle extras = getIntent().getExtras();
      mIMAGE_PATH = extras.getString("Imagepath");// 폴더 리스트에서 넘겨 받은 폴더 path
      String str = getIntent().getExtras().getString("folername");
      updateList();
      
            imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);
            imagegrid.setAdapter(new ImageAdapter(getApplicationContext()));
            imagegrid.setOnItemClickListener(new OnItemClickListener()
            {
             
             public void onItemClick(AdapterView parent, View v,int position, long id) {
                       Intent i = new Intent(Gridview.this, imageview.class);
                       //i.putExtra("filename", IMAGE_PATH + file.getAbsolutePath());
                       i.putExtra("filename", mIMAGE_PATH + "/" + ImageList[position]);
                       i.putExtra("imagepath", mIMAGE_PATH);
                       i.putExtra("imagelist", ImageList);
                       i.putExtra("currentposition", position);
                       startActivity(i);
                  }
                
            });
      }
      public void updateList(){
       File imagefiles = new File(mIMAGE_PATH);
       int i;
       if (imagefiles == null)
        return;
       ImageList = imagefiles.list(filter);
       imageList = new ArrayAdapter<String>(this,R.layout.imageitem,ImageList);
       imageList.sort(myComparator); //file sorting
       thumbsDataList = new ArrayList<String>();

        for(i=0; i<imageList.getCount();i++ ){
         thumbsDataList.add(mIMAGE_PATH+ "/" +ImageList[i]); // arraylist 에 파일이름 추가.. 전체 경로를 넘겨받음
        }
       //}
      
       
      }

   private FilenameFilter filter = new FilenameFilter(){
  public boolean accept(File dir, String filename) {
   if(filename.endsWith(".JPG") || filename.endsWith(".jpg")) return true;
   return false;
   }
 };
 private final static Comparator <String> myComparator= new Comparator<String>() { 
  private final Collator   collator = Collator.getInstance();
     @Override
     public int compare(String o1,String o2) { 
      return collator.compare(o1.intern(), o2.intern()); 
     }   
 };  
 
 

      public class ImageAdapter extends BaseAdapter { 

          private String imgData; 
           private String geoData; 
 
      ImageAdapter(Context c){ 
         mContext = c; 
        } 
    public boolean deleteSelected(int sIndex){ 
              return true; 
          } 
        public int getCount() { 
            return thumbsDataList.size(); 
         } 
        public Object getItem(int position) { 
            return position; 
         } 
         public long getItemId(int position) {    
              return position; 

         } 
          public View getView(int position, View convertView, ViewGroup parent) { 
              ImageView imageView; 
           if (convertView == null){ 
                imageView = new ImageView(mContext); 
                imageView.setLayoutParams(new GridView.LayoutParams(95, 95)); 
                imageView.setAdjustViewBounds(false); 
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
                imageView.setPadding(2, 2, 2, 2); 
               }else{ 
                 imageView = (ImageView) convertView; 
               } 
              BitmapFactory.Options bo = new BitmapFactory.Options(); 
              bo.inSampleSize = 8; 
              Bitmap bmp = BitmapFactory.decodeFile(thumbsDataList.get(position), bo); 
              Bitmap resized = Bitmap.createScaledBitmap(bmp, 95, 95, true); 
             imageView.setImageBitmap(resized); 
              return imageView; 

          } 
      }
}