User blog comment:DaNASCAT/Technical Update: January 6, 2016/@comment-1824272-20160107132130/@comment-5383971-20160107214143

Videos are no longer shown on Special:NewFiles.

We did not change the way the thumbnails are layout out. I just double-checked that on the test environment by reverting the code to pre-2016 state. Before this release the thumbnails were also grouped by 4 in line for wider screens and 2 in line for narrower once.

I agree it doesn't look fantastic, but I believe it wasn't broken now, but a good while ago.