If you create a page that contains just the SlickUpload control, and then host that inside an iframe on your main page, that should work. In the UploadComplete event of the control, set Visible="false" on the SlickUpload control to remove it, and then write out javascript that notifies the main page with the uploaded file information. If you want to automatically upload when a file is selected, take a look at this forum post: http://krystalware.com/forums/yaf_postst1374_Single-button-automatic-upload.aspx.
The other way you could approach this is to use a SlickUpload control on the main page. Set AutoUploadOnPostBack="false" and AutoPostBackAfterUpload="false". Manually trigger the upload by calling kw.submit("<%= SlickUpload1.ClientID %>"). Hook the OnClientProgressUpdate event and monitor for the progress to be complete. At that point, you'll know the upload is complete and you can display the picture. The drawback to this is that you won't be able to get information back about where the file is stored, as a full upload postback won't occur, so your logic will have to use a deterministic path to access the picture.
