Changing clip duration for multiple photos and transitions

There are two ways I have found to do this

First way: (Easiest and most straightforward)
Hold down the Command Key as you left-click all the photos you want to change. Then double click one of them to open the clip inspector that lets you change the duration. Enter the new duration, and click done. This will change the duration of all the selected photos.

This should work for transition durations, too, but I have not tested it.



2nd way (but it takes some advance planning.)

In iPhoto, create an Album. Drag all 2 second photos there (in the order you want them in the movie). Create another album. Drag all 3 second photos there.

Open iMovie. Set Project Properties for default photo duration to be 2 seconds, but only for new photos that are added. Open the photo browser. Drag the 2 second album into your movie. You can drag the album icon, rather than dragging the photos in one at a time.

Then go to Project Properties. Set the default photo duration to be 3 seconds for additional photos that are added. Then drag the 3 second album in from the photo browser.

Similarly, you can set default durations in project properties as when added as opposed to all.

Not the slickest thing, but it works.