Using the media gallery and cropping JUST the thumbnail, it displays correctly in the editing area but as soon as I go to the post it displays uncropped.
These are the steps:
In Edit Gallery click on image, then on the right – Edit Image
Click Apply changes to: Thumbnail
Enter an aspect ratio – I’m using 130×98
Click and drag in image whilst holding down shift.
Here’s the UNDOCUMENTED bit. Click the crop tool icon.
Click Save and Back.
It works fine in a duplicate testing site in localhost.