How big should a Firefox toolbar button be?

Question

What size, in pixels, should a custom Firefox toolbar button icon be?

I've seen quite a variety. Most commonly I've come across 32x32, 24x24 and 16x16 but also 10x10, 15x15, 16x14, etc. I cannot find a definitive reference.

Also see: How big should an Internet Explorer icon be?

Answer 1

Not sure how I found it, but the Creating toolbar buttons article at the Mozilla Developer Center defines Firefox big icon size as 24x24 and small icon size as 16x16.

Answer 2

There is no definitive size given.

The size of icon will depend on whether the user has large/small icons enabled. 32x32 is generally a good mid-point.