I am happy to help.
Here's another thing. After opening iMovie click on iMovie/Preferences from the menu bar at the top of the screen.
A preferences box will open like this:

Before you create a new project, you can pre-set the Photo duration and Transition duration from the preference box. That way you won't have to be changing them manually. In the Photo Placement box you also can set whether an imported Photo will be imported into the project with the Ken Burns effect or just as a regular still image. Again, the preferences need to be set before you create a new project, or they won't take effect. You always can override the preferences manually during the course of the project.
Have fun.
-- Rich