Ken Burns Effect for Vertical Photos

That is correct. When you crop in the timeline you are limited to cropping in the 16:9 aspect ratio of the iMovie screen. In other words, the start and end rectangles will always be the same 16:9 configuration no matter what size you make them.

However, you can crop to any aspect ratio that you want if you crop your photo in the media browser to the left of the preview screen. First you click on your movie's title under the Project Media heading at the top left of the sidebar. That will reveal in the media browser all the clips that are in your project. Select the photo that you want in the media browser, and then click on the crop tool as you would normally do. A little box with the word "Crop" in it will appear to the left of the preview screen. Click on the box to get an adjustment rectangle of the photo in the preview screen. You can drag the edges and corners of the rectangle by the little handles that you see, into any aspect ratio that you want. Then click the blue reset button to the right to apply your crop. So if you crop the photo to the horizontal 16:9 (or anything else) rather than the vertical 9:16 you can then apply the Ken Burns effect to it using the timeline crop tool.

-- Rich

After you "Fit" the picture you need to click on the little blue Reset arrow to the right of the screen. You will have black bars on each side of your vertical picture. Then do a Crop/Ken Burns and set the "Start" rectangle to encompass the whole picture, including the black bars. Then set the "End" rectangle to zoom in as much as you desire.

-- Rich