This is a little weird.
https://commons.wikimedia.org/wiki/File:Giuseppe_Barberis_-_Carlo_Cornaglia_-_Giuseppe_Verdi%27s_Don_Carlo_at_La_Scala.jpg thumbnails. That's fine.
https://en.wikipedia.org/wiki/File:Giuseppe_Barberis_-_Carlo_Cornaglia_-_Giuseppe_Verdi%27s_Don_Carlo_at_La_Scala.jpeg Will not thumbnal.
They are the same file. Similarly:
https://en.wikipedia.org/wiki/File:Giuseppe_Barberis_-_Carlo_Cornaglia_-_Giuseppe_Verdi%27s_Don_Carlo_at_La_Scala.png (local upload)
They are the same file.
https://commons.wikimedia.org/wiki/File:Giuseppe_Barberis_-_Carlo_Cornaglia_-_Giuseppe_Verdi%27s_Don_Carlo_at_La_Scala - Original.png
https://en.wikipedia.org/wiki/File:Giuseppe_Barberis_-_Carlo_Cornaglia_-_Giuseppe_Verdi%27s_Don_Carlo_at_La_Scala - Original.png (local upload)
Perhaps something has screwed up the en-wiki thumbnailing?
See also: https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#photos_in_an_info_box