Implementing two different custom providers for the different types of files is a valid choice for your scenario. You are also right that changing values in the web.config AppSettings for each upload would be overkill if you are about to upload millions of files.
Your suggestion to add path (folder) CloudUpload property that could be changed runtime could be a viable solution for similar scenarios of other customers too. Therefore, I would recommend you to log it as feature request in our Feedback portal
. Based on the support it receives from the community we will consider and decide on its future implementation.
Telerik by Progress
Do you need help with upgrading your ASP.NET AJAX, WPF or WinForms projects? Check the Telerik API Analyzer
and share your thoughts.