I am using this piece of code
add_theme_support( 'post-thumbnails' ); add_image_size( 'big-thumb', 640, 213, true );
However, the image thumbnail isn't being generated with that dimension. The height always remain 213px, and the image thumbnail is being generated proportionately with the height in spite of my crop setting.
What to do to get a 640x213 pixels thumbnail (resize only) from any uploaded image dimension?