Hi Mingbo,
The slice timing is indeed read from the first image.
If they have populated that with garbage, one workaround
might be to include an extra image #2 at the beginning,
and then remove it afterward. That might be the easiest
thing to do right now, e.g.
to3d -prefix temp ... FROM_IMAGE IM2 IM1 IM2 IM3 ...
3dTcat -prefix fixed temp+orig"[1..$]"
- rick