can i put a transparent photo on top of a video

O.K. Now I think I see what your friend is trying to do. Is this the effect that she wants? It is a transparent angel overlaid with Picture in Picture, and made to float in by setting keyframes at specific points in time.

The procedure that I described in my earlier post will create a transparent background for the photo, but won't make the photo subject itself transparent. To do that you would need to use the lasso selection tool in the Preview app to outline (select) the photo subject, then copy--paste it on the transparency screen. As I recall I then imported the transparency screen photo into iMovie, overlaid it onto the background clip with Picuture in Picture, and used the fade handles to make the overlaid photo subject itself transparent. (When you add a fade it makes the clip transparent for a period of time.) Then I exported it out and imported it back in and trimmed back the clip a bit so as to stop the fade before it became opaque again. I know this sounds a bit complicated and may take some experimenting and practice. The end effect was pretty good, though. The transparent angel floated in and became larger as it reached the foreground of the clip.

Post back if you have any questions.

-- Rich

Here's an online help link that explains in step by step fashion how to use the Picture in Picture feature of iMovie to overlay a picture onto another clip and impart animation to it.

https://help.apple.com/imovie/mac/10.1/#/mova1aaa682b

And here is a screen shot of the fade handles that I was talking about:

-- Rich

If you have a photo of the person with a green or blue background, you could also use a chroma key - blue screen or green screen. It is not always necessary to make the background transparent.

Great! Glad it worked for you! 😊

-- Rich

Yes, that is possible. Not exactly sure what effect you are trying to achieve. Could you post a screen shot of your photos and describe what you want to do?

Generally, you can use the Preview app on your Mac to create a transparency screen, and then copy and paste your photo into it. Then save and drag into your iMovie upper timeline aboe your video clip. Select it and overlay it with the Picture in Picture feature.

Here's a link to an previous post of mine that describes how to create a transparency screen. The post was showing how over lay an arrow onto the a transparency screen, but the same basic procedure would apply to a photo.

https://discussions.apple.com/thread/251193354?page=1

-- Rich

-- Rich