Image duration not working

I've got iMovie 10.1.2 and I'm really sorry that I deleted the older version of iMovie . Trying to put together a Time

-Laps video with a sequence of images I've taken. In this video i would need to get the image duration down to < 1 sec (ca 0.05-0.5 sec), but it's not possible to adjust the duration which seems to be stuck at 4 seconds . Anyone have a good idea for a workaround or other software LTR4 is really good . but require Lightroom asa "buddy".