How do i create a 6 x 4 photo

Hmmm, the obvious answer is to start with a camera, but I suspect that's not quite what you're asking here 😉

Do you want to crop one? Print one? What are you staring with? 6 x 4 what? Aspect ratio? Inches? Centimeters?

What system and iPhoto versions are you running? What size are the images you're working with?

Crop the image to 4x6 and print selecting 4x6 as the print size

LN