Images in Photos, iPhoto and Photo Booth may be opened as a new drawing file, and/or added to an existing drawing.
Drag-and-Drop Photos, iPhoto & Photo Booth to Existing Drawing
Choose ‘File > Open…’ from the Artboard main menu. Choose an image from a folder or from the Media Browser. Drag-and-drop image to your drawing canvas.
HINT: You may need to scroll down the sidebar to see the Media browser.
HINT: The Media browser will display iPhotos or Photos depending on the version of Mac OS X you are operating.
Open New Drawing with Photos, iPhoto & Photo Booth Image
Choose ‘File > Open…’ from the Artboard main menu. Choose an image from a folder or from the Media Browser and click ‘Open’ to open an image as a new drawing file.