Text Align buttons disabled

Dear all,

I am a little bit new to Contribute, but have created a site that is working pretty well. The only issue I'm having is that the ability to align text (center, left, right, justify) is disabled in Contribute - the buttons are grayed out. I have gone into administer roles, and I don't see anything that restricts this in particular. Everything else is enabled - fonts, font sizes, font colors. Only the alignment is disabled.

There is a need to be able to center images on the site. Is there something I'm missing that can get this enabled?

Thank you.