When I was using Windows 7 I could drag and drop an attachment and it would display a thumbnail and the file size.

After upgrading to Windows 10 an odd thing started to occur. When I dragged something into a new mail message it now just shows a filename and a blank icon.

HOWEVER, if I attach a file via the paperclip icon and select a file from the pop up menu, the thumbnail and file size returns.

I figured this must be a glitch/bug of some sorts.