Printed photos not true to size chosen
I have a photo frame with a several openings for 4x6 photos. I've tried to print photos on glossy 4x6 photo paper to fill these openings, but even though I selected no border, there is still a narrow border on the top, bottom and left side and a very wide border on the right. Obviously these photos don't completely fill the opening in the mat. How do I resolve this? I'm using Photos and a Canon Pixma 2820 to do the printing.
iMac 21.5″, OS X 10.11