Print a Montage

I have 2 HP printers (Deskjet 6122 & Photosmart D7160) some time ago I did print a montage which had about 12 or so photos of different sizes and for the life of me I can not remember how I did it. It did not seem, as I recall, to be very tough to do, but one of the joys of being 88 years old is memory fades.
Can anyone help me?
Ralph