It is not possible. How does the browser know you have selected suppose in a order like 1,5,3,4,2. For that you have to select one image at a time.

Or you can refer the below article that will fullfill your requirement.

Uploading Multiple Files using FileUpload Control in ASP.Net 2.0, 3.0 and 3.5

HTML5 multiple file uploads is controlled by browser so it cannot be predicted for sequence