I see an easy way to implement small icons is to create a new navigation bar that uses small icons without text and user preferences can change the toolbar from toolbar = use large navigator bar toolbar = use small navigation bar sounds like some XUL, Widget and themes, not that hard to implement.

dup of bug 22056? If this is about the classic theme, there's a contradicting bug 59708: reporter there thinks the icons are already too small.

yup. *** This bug has been marked as a duplicate of 22056 ***

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