When you do that, you’ll get the opportunity to tell iPhoto how many you’d like of each.
As you can see above, you’ll edit the number that appears next to a size to indicate how many you want. If a particular size would look bad on a photo you’ve selected because of its low resolution, that’ll be indicated by a yellow exclamation point icon.
You can also use the “Quick Order” drop-down menu in the upper-right corner to add on, for example, a 4-inch x 6-inch of each chosen photo all at once. To do so, switch the “Quick Order” menu to your preferred size, and then click the arrows next to it to adjust the quantity.
Then repeat for any other sizes you need.
After you’re satisfied with your selection, click the “Buy Now” button, and then complete the order with your shipping address and so on. If you have an Apple ID with an existing credit card attached to it, the process is easy as pie—just sign in with that info as a returning customer.
One final note: Be aware that the shipping cost can be kind of high, especially if you order only a few images at a time.
Obviously, it’s in your best interest to get a bunch of prints at once rather than in smaller batches.
So now you need to get some pictures printed out of your holiday celebrations, right? All of the food and merriment? I won’t be doing that, just so you know. No one needs to see that picture of me wearing antlers.