in setPicture() you need to set a url for the image that you want to share.
FacebookDialog shareDialog = new FacebookDialog.ShareDialogBuilder(this)
.setPicture("http://yourdomain.com/images/test.jpg")
.build();
uiHelper.trackPendingDialogCall(shareDialog.present());
i see
try with this
Bitmap bmp = R.drawable."bitmapFileName";
to take your bitmap from a drawable folder and...
protected Builder addImageAttachment(String imageName, Bitmap bitmap)