Uploadify - button image css

Question

As I know uploadify button are able to customize the css of the button ... How bout the button image ?

In my current uploadify button I'm using:

'buttonImage' : "images/jpg_icon.png", // image size 50x50

The image doesn't show single ... it repeat and repeat ...

I tried css it in uploadify.css:

.uploadify {
   position: relative;
   margin-bottom: 1em;
   background-repeat:no-repeat;
}

but so far button image are set in uploadify JS ...

Any suggestion to do it ? Thanks a lot