Stock Size Card SizePrinting to custom sizes other than the standard can be done but the card will have a small white border on both sides of the card. The border could be trimmed off with a paper cutter to produce a borderless card.
8 x 10 borderless ............……........... 8 x 5
5 x 7 borderless .........……................ 5 x 3.5
4 x 6 borderless ..................……....... 4 x 3
1 - While in the card mode type Command-P to bring up the Print window.
2 - In the Print window select Paper Handling from the iPhoto drop down menu.
3 - In the Paper Handling pane select the paper size you want to use in the “Paper Destination” drop down menu and check the “Scale to fit paper size” checkbox.
4 - You can now print the card to the stock size selected. To give you time to flip the stock after the first size is printed it’s easiest to just print Pages 1 to 1, flip the stock and print Pages 2 to 2.
However, if you do a Print to PDF and save the card as a PDF file you can print one page at a time without having to re-processing the card. The PDF also lets you more easily print multi copies of the first side, flip the stock and print the other side easier.