Jonathan said:setting the background-image of .sfsearchSubmit should be correct. I had to set the height and width explicitly. See below to see if that helps. The below will create a nice huge red button. The important is optional.
If that doesn't help if you paste your CSS here?
Got my image working good Jonathan.
Problem is that:
Is still there so I see proper image, proper BGC but then I still see the ugly word search go accross it. Any help would be awesome