As you noticed the background for the Select
button is an image that you move to X,Y coordinates(e.g.
background-position: 0 -46px
You can load your own picture for background with a proper size and color by using the following CSS class:
/*RadAsyncUpload1 is your control's ID*/
. RadUpload_Default .ruButton
/*it is an example URL*/
I am sending you the background picture from our demo.
the Telerik team