Here you can upload and save up to 10 MB of images without any postback
(Callback is used).
(the following CheckBox doesn't effect on IE with version number less than 10)
Source code of this example can be downloaded with the Suite
/FileUpload/cs_WithoutPostback.aspx and /FileUpload/cs_WithoutPostback.aspx.cs
/FileUpload/vb_WithoutPostback.aspx and /FileUpload/vb_WithoutPostback.aspx.vb