Ajax file upload control in C# - repost

I need an ajax file upload class control that will do the following: 1. Upload multiple files via drag&drop and via selecting 'Browse'. 2. Can only upload image files and pdf. 3. When the upload is complete, show a thumbnail of the uploaded image/pdf on the webpage. This needs to be written in a c# asp.net solution project and full source code has to be provided with documentation. Funds will only be paid when job is satisfactory and functions fully tested.