Mike - You were entirely correct, although I initially went about it in a wrong way by copying the entire function.php from the 2010 theme into my child directory and then modified the image settings. That created a host of other conflicts until I learned how to do it properly. I created an empty functions.php in my child directory and then copy/pasted only the clearly commented section related to header mods into that file and then set both, Height and width to zero.
The function.php in the child directory is READ FIRST, so whatever I declare there takes precedence over what exists in the default theme function.php. Basically one has to be very thoughtful about what NEEDS to be in the child's function.php, and nothing else. Thanks again. Mike