Is it possible to offset a quad in a rich text box

I have a text mesh that is marked for rich text and I'm trying to include an inline image. I'd like the image to be centred to the middle of the text. But that's not what's happening:

It's offset (what looks like) to the centre of the image. Is there a way to change that offset to align it with the centre of the text?

The text used for the mesh is:

 "Press <quad material=1 size=24 x=0.0 y=0.0 width=1 height=1 /> to continue or <quad material=1 size=20 x=0.0 y=0.0 width=1 height=1 /> to quit."