Currently Being ModeratedFeb 11, 2014 2:59 AM (in response to AppleIncWizard)
If you select your project and click Settings (above Viewer) you can set the default clip duration (field marked "Clips:" to 1 second by moving the slider fully to the left. All photos subsequently added to the timeline will then automatically be 1 second in duration.
Currently Being ModeratedFeb 11, 2014 4:22 PM (in response to AppleIncWizard)
You go to iMovie > Window > Movie Properties > switch the Zoom to Fit and set the duration to 1 sec.