Here's the sceenshot of the error I get when the file is uploaded:

 

Also, the link you have posted does not offer any help regarding a custom provider for the AJAX uploader. Please note that this situation is not related to saving images into a database. I already have a custom provider that allows me to save my images to a database and it's working fine. What I am trying to do is prevent the uploader from writing temporary files to the hard drive.

 

I looked at CuteEditor.dll in .NET Reflector and found the following line of code is probably causing this problem:

 

It looks like the FileBrowserPage class is assuming the temporary file is on disk and attempts to use a FileStream to read the content.