You can add multiple images (or logos) to the foreground of any scene. You can also add a single image to the background of any scene. This article deals only with adding foreground images.
To add multiple images to the same scene:
Down in the timeline, select the up arrow on an existing caption, then "Add image caption". Or hit the plus sign in the timeline, followed by "Add image caption".
Upload your first image and position it on the canvas
Click on the first image in the canvas and click the "+" plus sign
Upload your second image and reposition as needed
Rinse and repeat to add more images
You can add an unlimited number of images to any one scene. Just remember, less is always more. Your video is likely to look better with fewer images.