Firefox 3 has the new icons for Back and Forward web pages button which assembles the keyhole style, some may says it looks like an arrow on steroids. The Firefox 3 new button style has the Back button a slightly bigger size than the forward button.

Firefox 3 Keyhold Back and Forward Buttons for Windows, Linux and Mac OS X

For user who prefers the smaller size of Back button, or at least has the same size with Forward button on level ground, user can opt to shrink the Back button size to make it smaller and on par with Forward button.

To change and make Back button smaller, right click on empty area on toolbar, select Customize, and then check the checkbox for Use Small Icons option. Click Done.

Firefox 3 Small Back Button

The Back button will now be smaller in size, and has the same size as the Forward button. Note that enable the “Use Small Icons” option also make all other icons on the toolbar looks smaller.