When using Chrome, thumbnails might be split on two columns if they are inserted within a column.
Example: https://it.wikipedia.org/w/index.php?title=Parco_Natura_Viva&oldid=97414977
The file is listed between Stegosaurus and Camptosaurus in the code
*''[[Stegosaurus]]''
[[File:2 stegosauri.jpg|miniatura]]
*''[[Camptosaurus]]''
and as you can see the thumbnail is split. Using Microsoft Edge, however, the thumbnail isn't split:
The issue became more evident when I tried to add a caption:
Chrome
Edge