Images freeze on last frame and don't display

Whenever I drag an image from either the iPhoto section within iMovie, iPhoto itself or my desktop into my iMovie project and play the movie, when it gets to the image the video carries out the same procedures as it usually would if an image was there but instead of displaying the image, it shows the last frame before the image. Also, when I go to edit the image, for example change the Ken Burns, it continues to show the last frame of the previous clip. However even if I put the image before any clip, it will simply take a frame from the clip below and display that instead of the picture.
Help ASAP will be much appreciated.
David