The requirement for landscape images is to be at least 320px
wide. The requirement for portrait images is more relaxed,
only 250px high. Images that fall between these two
requirements currently don't show a thumbnail, even if they
could.
This change affects a very specific group of images:
* Square images from 250 x 250 to 319 x 319.
* Landscape images from 251 x 250 to 319 x 250.
* Landscape images from 319 x 250 to 319 x 318.
The most extreme ratio is 319 x 250. This will be cut to
203 x 250. I.e. the absolute extreme are 58px missing left
and right, but never more.
Requested at https://www.mediawiki.org/wiki/Topic:Vwl97pm6as9fuf6k
Additional stories for testing more extreme small images:
* Small Tall - 300x1000px
* Small Short - 300x200px
Update tests accordingly.
Bug: T268999
Change-Id: I811f1c0e7e9b0c30280b36a61cc7831a5b9e58c8
