...with a bit of thought, you could get to the point where they are all at least centred, (transform sequence on multiple selected frames), then shift one down to the bottom, and again select remaining frames and apply a transform again command...
...of course, this is largely dependant on image size and remaining space left between top and bottom of frame, if they are all the same size images in the same size frames, then this would work pretty well for example...
Andrew