PIXMA TR8520 How to print 4 images on a 4" x 6" sheet

[resawd21]

Using TR8520 on a W10 HP.  Trying to print 4 iomages on a single sheet  of 4 x 6 glossy paper. There are 12 images in file but printer app only allows a choice of 5 of them.  How do I get the app to allow me all of the images?