What’s the answer?
You make the image slightly larger than you actually want.
So if you want an A4 leaflet (297x210mm) which has an image
that goes right to the edge of the sheet, you create the image 3mm
larger on all 4 edges (303x216mm).
The extra 3mm on all 4 edges should be parts of the image that
you don’t mind being cut off.
You want this.
So you design this.
(The dotted line indicates where we will cut to).
If the image shifts during the run it won’t matter. Once the stack is cut, the
knife’s edge will still slice through some printing and it will look fine.
The image will
off the edge of the sheet.