I think you might need to look under Settings > Media and see what the image sizes are.
And if the “Crop thumbnail to exact dimensions” is ticked.
The box is not ticked.
The maximum dimensions are set to:
THUMBNAIL
150×150
MEDIUM
300×300
LARGE
1024×1024
Also:
Image sizes are defined by the current theme
The sizes listed below are the crop and resize formats defined by WeeklyNews
There are many options but when inserting into a post, you can only insert square images or the full size.
Thanks, though, Robin.