iphotos used in imovies

I have created 2 movies in iMovie that use some videos uploaded to iMovie and also some photos from iPhoto. I have since decided to move all of my photos to Adobe Lightroom. To do so, I have exported photos by event from iPhoto to a new location, imported them into Lightroom, and then deleted the event from iPhoto. For the iPhoto events where I have used photos in iMovies, I have yet to delete the events from iPhoto. I assume that iMovie will be very confused about the location of the photos and will no longer be able to play the movie. Should I just keep these events in iPhoto in addition to having a copy of the photos in Lightroom? Can iMovie "see" photos in Lightroom? I have 2 goals here: 1) not break 2 existing iMovies that use photos from iPhoto, 2) be able to create new iMovies using video and also photos from Lightroom. Is this possible?