Screengrab of file page, including history and thumbnails as rendered.
Thumbnail images which are kept on file pages, in the second column of table "File history", are "squashed" when created from wide, short images.
The thumbnail created from the 320x226 (6k) version of the image was correct.
Border reduction was requested, so I did that, starting from the 4961x3508 (1.69 MB) master file. This produced a in 320x87 (20k) image, which when uploaded, produced a "squashed"
This appears to be because a new thumbnail was not actually created. Instead, the previous thumbnail was used:
https://upload.wikimedia.org/wikipedia/en/thumb/d/dc/PharmaSecure_Logo_TM.jpg/120px-PharmaSecure_Logo_TM.jpg - note borders still present
and was sized within the <img> tag, making it look squished.