I'm not sure if the drag&drop operation is the problem here.
To me it seems more like the presentation of the files could be problematic. You are trying to do this for multiple files, right? LabVIEW isn't the language of choice when trying to make pretty UI stuff.
OTOH I haven't used movie maker for a long time so I can't quite remember how it represents pictures - I'm imagining tiles (There's a demo somewhere that shows how to implement windows 8/10 style UI tiles on a FP but I can't find it now). But as a newcomer to LV, you'd be entering the world of pain.