Image cropped by default/

Would anyone know why my images are cropped by default & how to fix?

Example:
http://www.rickymangala.com/

The full image should look like:
http://www.rickymangala.com/wp-content/uploads/2015/09/website-background.jpg

I’ve changed my media settings to allow Large 1920 x 1280 and re-uploaded but no luck.

Is there anything I’m missing or need to do to the wordpress CSS?

Thanks