I have just carried out a test regarding no images.
My test is on El Capitan, but this should be the same on your Sierra.
I copied my copy of iMovie HD 6.0.4 onto MB Pro running El Capitan.
Like you I got the "no images"
This was hardly surprising as I do not have iPhoto installed on El Capitan.
I went to App Store and looked in Purchases and could see iPhoto was offered as UPDATE.
I downloaded this and installed.It is version 9.6.1
I placed a photo in the new iPhoto.
I opened iMovie HD 6.0.4 and the photo appeared in media photos.
You need at least iPhoto 9.6.1 for it to run on El Capitan or Sierra.
If you have previously updated iPhoto but have not got 9.6.1 then you should be able to see the update
in your Purchases in the App Store.
You will of course have to populate the new version of iPhoto with all your photos
but I am assuming this is not difficult; i.e. copy them over.
Just to say that before going onto the App Store I did copy over an old version of iPhoto
onto the El Capitan desk-top.This of course had the NO ENTRY sign on it.( no the trick doesn't work,I tried)
This old copy may (????) be needed on the desk-top in order for the update to take place,I am just guessing.