Thumbnails Slow

I backed up my iPhone Camera Roll to the Stick.  When I try to access from another device (iPad) it only shows some of the pix as thumbnails and most of the others only show as file names unless I click it open.  Any advice on how to show all the thumbnails?

IIRC currently the thumbnails can generate slow if a large number of files were recently added and they are working to improve the thumbnail generation time in a future update. 

Yes I have about 2000 pix.  I hope they improve the time since this was a key reason I bought the drive.  Thanks.