Background image for each comment

I am trying to have the same background image display with each comment. But despite adding the appropriate CSS, it will not display.

Since I’m in a hurry to get a site up for an organization, I have hacked kses to allow images and just pasted the code in manually in the body of each comment before approving, but now this image also shows in the comments admin page!

If anyone can suggest an easier and more elegant solution, thanks in advance.