Automatically Center Footage

I’m new to Natron, and don’t quite understand how to do things efficiently yet. Suppose I want to composite several layers together that are NOT the same resolution, and the project resolution is 1920x1080. Whenever I use, for example, the image read node, the image is NOT placed in the center of the 1920x1080 canvas; instead, it is aligned by its bottom left corner.
Example:


What is the most efficient way to center items with different resolution to the canvas? I can obviously do the math and translate it by the appropriate amount, but this is not a good use of my time.

The main reason I ask is because this is the default behavior in Adobe programs (which is what I’m used to), and I find easier that way. Any help would be appreciated.