Keynote - importing iMovie clips and stills

Hi there.
For the first time, I've had to put iMovie clips and still shots into Keynote. I was advised to download and use version 6 of iMovie but I've had two problems putting data from iMovie into Keynote.

1. The clips I copied into Keynote yesterday worked fine. However, when I now copy an iMovie clip into Keynote, it copies the whole movie file, not just the clip. Can't work that one out.

2. More strange: I have been making some 'snapshots' or 'stills' in iMovie and pasting them into Keynote. Mostly, they have worked fine. However, one of the stills goes into Keynote ok, but when I keep working and come back to that slide later, a different still is in place. Strangest thing is that the original 'still' still shows in the navigator column down the left-hand side while the 'random' one appears in the main window. The 'random' one doesn't even come from the same movie file! I don't know how it picked up a still from a different iMovie file that wasn't even open.

I hope I've explained the problem adequately. It must be difficult for someone else to understand what's happening here, but I will appreciate any help.

Thank-you
David