Image overlay issue in imovie

Hi I am trying to put an image overlay into imovie. It was working earlier, but now it will not let me drag the image on top of the video clip. Everytime I drag it an x comes up and it will not let me drop. I tried saving the image to my desktop and then importing it that way. It still gives me an issue and when I press "Import" it stays stagnant and even if I click it a numerous amount of times. This literally just started to happen because I've never had issues with dragging and dropping an overlay image into imovie. I tried restarting, making a new project, shutting down. Nothing will get it back working again.