Printing digital photos as 4x6 using iPhoto
If you have a photo that has a different aspect ratio (like 4:3 which is typical for digital cameras) and you try to print it in a 3:2 ratio (Ex. 4x6) it will not print all of the photo. There will be cropping.
Your choices are:
1. To first crop to 4x6 so you control what gets cut off and what is included. Select and open your photo, click on Edit. Select Crop. Check Constrain and choose 4x6 from the drop-down menu. Adjust the box to your liking. Click on Done.
2. Use the customize screen when printing. Select the photo, select print. Choose your printer, paper size, print size. Click on Customize. Right click (Control-click) in the photo preview and select "Fit to Frame" which will add white space fill so the whole image will print.