This is driving me crazy - Image size printing question

[Clueless]

I need to print a 110mm square image centered on a A5 sized canvas (the image consists of 3 elements - the image itself and 2 borders) I have set the canvas size to A5 centered the image correctly but i cannot get it to print the correct size. I have tried both the resize options on the template canvas resize dialogue screen but I can only get a image 70mm square to print - help !