After a week of banging my head against the wall, I am now able to get the Custom Header function to work, correctly as far as I can tell. Howsomever, I have a question regarding its functionality. Here goeth ...
It appears to me that the crop function works on a specific aspect ratio, within the limits of the image that is to be cropped. Whatever limit is reached, whether it is the height or the width of the uploaded image, that is where the crop stop. (Okay, that was supposed to be a pun. It should have said "stops," but I couldn't resist myself.)
That seems reasonable.
However, the instructions on the Custom Header page say "Images of exactly 960 x 150 pixels will be used as-is." But when I put an image of the size specified, a significant portion is cropped. If I reduce the width of the image, them I lose a portion of the image height and the right side of the image is still cut when displayed. The only way I have been able to solve the problem is to leave a significant portion of empty space on the right side of my custom header.
My guess is that having to do that will frustrate my bloggers.
So, what is happening, and is there anything I can to to make the image resize to fit the allocated space?