Dear Tamimun,
first of all, it is not a problem.once you upload image and it is saved to your diectory, there is no need to keep that text in your control otherwise when you click upload again it will be uploaded again and again.There is no solution for that.
Yes one alternative is there.
You can use agax contol toolkit.
and use Asyc file upload control from toolkit..
use this link for more ....
http://www.asp.net/ajaxlibrary/AjaxControlToolkitSampleSite/[
^]