I've noticed in reading old threads on button removal that no one clearly addressed removing the file information button "i" button. It doesn't appear (or seem to be obvious) in theme.php. How exactly can this file info button be commented out from theme.php.
Copy the navbar template from the sample theme into your theme and comment out the button. Has been discussed before I'm sure.
Take a look at the thread "How to remove "Slideshow" and "Display/HideS Image Info buttons? (http://forum.coppermine-gallery.net/index.php?topic=43913.0)" for example. If found that thread using the forum's search feature (http://forum.coppermine-gallery.net/index.php?action=search) as Nibbler suggested.