Thanks to both responders.
I do have autoframe on, as it seems to be on by default. I will turn that off and try again. I am not in the Master Page edit mode when I attempt to insert an image, just in the regular mode, so to speak. But autoframe has already caused me other problems (like linking boxes that I would prefer to be separate), so I'll deactivate autoframe and go from there. Thanks again.
I'm using version 1.4.8.