PNG images with transparent sections

In CloudPebble Javascript environment. Can I render a base image and then render an image with transparent sections over it such that the base image parts under transparent sections show through?

I know I could just try it, but thought it would be good to know whether it will work at all.

So far I’ve used complete faces with slightly different artwork and switched them out under certain conditions. If I could change just part of the image with an overlaid image that is mostly transparent I expect it might lower memory use.