Unix command to recursively copy JPG files in a complex directory tree
You can easily use rsync to accomplish this:

rsync --include "*/" --include "*RNav.jpg" --exclude "*" -am source destination


Based off this page. This includes folders and *RNav.jpg files and then excludes everything else. I've used -a instead of -r to preserve more information (my personal preference) and added -m to prevent rsync from creating any parts of the directory tree that wouldn't contain any files.