In order to import photos into PrintMaster from iPhoto you will need to make a local copy of the images inside iPhoto onto an accessible area of your computer.  

How open picture files in iPhoto. 

Open Finder:

    1. Click on Macintosh HD

    2. Double Click on the users folder

    3. Double Click on the folder for your account (one with the house icon)

    4. Double Click on the Pictures folder

    5. Press and hold Control on your keyboard and then click on the iPhoto Library Icon

    6. Click on the option for "show package contents"

    7. Double Click on Masters Folder

    8. Notice the folders by date (2014, 2015 etc) “All images are stored on date imported”

    9. Locate the folder with the images you are looking to use and select the images.

    10. Hit Command C to copy the images

    11. Select a folder on your computer to store images

    12. Hit Command V to paste the images into new location.

    13. Open PrintMaster

    14. Click on Add a photo

    15. Now navigate through the folders to find the picture you wanted to import 

Alternatively you can select a photo in the iPhoto application and the under file menu select 

export (Shift-Command-E).