The really big problem is that you posted in the iPhoto for Mac forum so of course the answers are about how to do it in iPhoto - for help on Preview you need to use the Preview Help menu or post in the forum for your OS
and you originally talked about using iPhoto
As to selections, in iPhoto's print window, I have
Presets: "Photo on Glossy Paper - Fine"
Feed from: Photo Tray
Media Type: Photo Glossy Paper
Quality: Bestg
The correct Detailed procedure to print a 2" x 2" photo is
Using iPhoto '11 version 9.5.1
select the photo - crop to 2x2 - go to the file menu ==> print - in the resulting window select the printer. the aper size (this willl NOT select a paper source - it onlys sets the print size to be sent to the printer) - paper type (if offered - it is no clear what this selection actually does) - then select the custom print size and at the bottom set to 1:1 ratio and 2" x 2" print size -
at this point the iPhoto preview window will reflect your selections and ahow a preview of what will print
click print and you will get the Printer driver window - click on show details and set printer specific options (these have nothing to do with iPhoto and are different for every printer - the settings hre may or may not actally select a paper source - that is up to your printer softare)
Then Print
The program Preview is not involved in any way
iPhoto does NOT select a paper source - your print drive may or may not - you may have to have the correct paper in the main paper source depending on your printer
LN