Alignment not working in text tag?

I've embedded an image in my body text and I'd selected center in the UI and I see its syntax in the tag, but looking at the rendered page it's still aligned left. Firebug only shows the imagecache related classes, nothing that I could use as a CSS hook other than for that specific image.

I didn't flag this as a bug because I can't imagine it would have slipped past testing, reckon it has to be something specific to this site?

Note I happen to have the same asset linked from a CCK field - just testing at the moment, but my intention is to have an embedded thumbnail in one (single) field for use in teaser mode/table Views, and then other full-size images in another (multiple) field for creating a gallery-type display. I'd want both of these fields hidden by default in a normal full node view, but then choose the ones I want to display inline using the text tags.

So beyond the immediate issue, I'd appreciate feedback on whether I'm on the right track for this, I'd like to see Asset giving me a good combination of the features from Image (+ Image Assist) (or Inline) as well as Imagefield. . .