I renamed this image and tried again. It didn't change the size this time. The first time it resized the image, I guess it was normal because the image was larger than the config settings, and the resize option was true, but after deleting the file from the server and uploading again, it seemed to always go back to that small size. Maybe a caching issue (???).

 

Anyway renaming the file and trying again led to successful upload without it resizing it for me.

 

Thanks