I don't know how to import the Quicktime file into iMovie
In iMovie, go to: File > Import Media and navigate to the required clip
edit the Quicktime file into individual clips
Click on the clip in the browser
Drag the yellow handles at each end of the clip to the required position
Click the plus + button on the clip to add the clip to the Timeline
Can I convert Keynote into GIF (moving pictures)?
No, you should not do that for what you are trying to do
I think I can directly make MOV file without conversion from Keynote.
then give that a try
How can I lengthen the seconds for one photo in I-movie?
add the still image to the timeline
position the cursor over the right hand edge of the clip until a double arrow appears
now drag the clip edge outwards to the right
a timer will appear while you drag the cursor showing the duration of the clip