Partial Overlay of Static Image:

I had trouble merging tracks containing static images. Here’s how I address that challenge as I describe it in the course I’m building,

(Overlay)
Some techniques require the clips adjoined on the same track. I’ve found a number of ways to do that wrong. One of the safest ways I’ve found to do it right involves compositing.
I create my composite on the V2 track then unlock the V1 track. I next turn to the Timeline ribbon. I keep the snap toggle, the magnet icon, on. But I toggle everything else off. That’s important. Otherwise everything in the V1 track will slide over and it becomes a big mess. It took me a long time to figure that out.
Once I clear the ribbon, I simply drag each clip from the V2 track straight down onto the V1 track.