How did you trim your Taiwan passport photo to be exactly 45 x 35?

Everywhere I went in the U.S., the store said their machine cannot cut the passport photo to the Taiwan size, and that I have to cut it myself.
The Taiwan passport photo requirement if 45 mm h x 35 mm w. The background has to be white. This means there are no lines to guide for cutting. I am realizing that to cut the photo to be exactly 45 x 35 is not that easy. Do you know if TECO will allow some leeway for it to be off by 1 mm? How did you trim your passport photo to be the correct size?

9 posts were merged into an existing topic: How strictly did your passport photo match the face size requirements?