I am using unify bootstrap template theme parts for this AJAX s3 Upload Example.
Theme can be change very easily from the _layout.cshtml
Dont worry if it does not render good.

Requirment :
1. unobtrusive-ajax
2. aws.s3
3. any bootstrap theme (optional)
4. jquery libs are very imp

The reason to create this code is to easly plug the code in any project and play.
// Note : if user doesnt want to use the aws.s3 then other service provider can be integreated very easliy
// The image will be avaialble aprox 1 min available and then deleted as its a demo version.

Single Upload by ajax

Try small size, if there is an error.

Multiple Upload by ajax with Thumbnails

Try small size, if there is an error.