It is true! You can swap out image for footage and vice versa!
Here's how to swap your images and footage in your video:
Simply locate the image/footage you'd like to swap out or change on the editor panel on the right-hand side.
Click on the image/footage and and click Replace
Your Asset library will now open showing Images and Footage tabs, click on either!
Simply select the image/footage you'd like to replace it with.
TIP: Click on Edit on your image/footage to adjust your positions, framing, or adding filters and effects!
Check out this article for Editing Images and Editing Footage
Currently, videos generations VIA Variations may not reflect some changes made to the original videos during editing (e.g. images-footage swap)