Depending on what you mean by "merge," you can use PiP (Picture in Picture) to have the second image come in and occupy part of the screen with the original image. There are many ways to display PiP, from say a small image located in the screen to having it occupy one half of the screen.
Does that sound like what you are hoping to do?
Besides the rather simple PiP, one can also use Track Matte Keying to bring up the second image and to soften edges, drop it into an image of, say a TV set, or a window.
The possibilities are endless, or nearly so.
Let us know if PiP works for you, or if you need a more intricate merging of the images.
Recently I wrote details for a PiPs application for another forum that I frequent. You may want to check it out to determine if the approach would be helpful in your project.
I played around with it and was able to figure it out by placing one still on video 1 and the other on video 2- both occupying have the frame.
Thanks for replying,
I played around with it and was able to do get what I wanted by putting one still on video one and the other on video 2 and filling half the frame. I will try the PIP next time.
For the most simple versions of PiP, a layout, as you have chosen, with some Effects Motion>Scale and Motion>Position, plus maybe some Effects>Crop, will give you what you want.
Beyond that, there is a world of additional Effects that one can add to create some unique and wonderful compositions.