Choose the Load button in the Design Manager – Item or Component - Picture tab
Double Click the Pictures Directory/Folder in the Windows browser window
NOTE: you may need to go under C:\Users\Username (of the Computer) to find Pictures:
Double Click iPhoto Library
Double Click the Masters folder
Double Click the year the picture was imported/saved into iPhoto
Open the Month
Double Click the date the picture was imported/saved into iPhoto
Highlight the Picture you want to Import/Load into DM
Click Open
Click OK to Save inside the DM PIcture tab