Printing 4 photos 4x6 in one page

If you are using 8.5x11 paper it is physically impossible to print four 4x6 photos on a page. If you total 6+6 inches = 12", 1" inch larger than the 11" of the page, and that without having any borders between the photos.

In Windows, selecting 4 photos and sizing them to 4x6 will be automatically placed in only one page

This is NOT POSSIBLE unless you have a tabloid printer and print on 11 x 17 paper - four 4 x 6 photos take a minimum of 8 x 12 - larger than either an A4 or letter sized paper - and the laws of physics forbid printing 12 inches of data on 11 inches of paper.

The MAXIMUM you could do with no borders would be 4 x 5.5 photos (which as you note is smaller that 4 x 6)

LN

A4 paper, according to the print dialog window, is 8.27 x 11.69 inches. You still can't get 4 4x6 photos on it. They must be 4 x 5.845, slightly reduced.