Feature Image Size Overwritten

Hi,

I am using Twenty-Fourteen Theme and I customized it. My feature images are being scaled down to 1038px x 576px making them blurry. The feature image in the link below was uploaded as 1920px x 1269px.

I found this code in the function.php file:

// Enable support for Post Thumbnails, and declare two sizes.
	add_theme_support( 'post-thumbnails' );
	set_post_thumbnail_size( 672, 372, true );
	add_image_size( 'twentyfourteen-full-width', 1038, 576, true );

So I changed it in my child theme functions.php file to:

if ( function_exists( 'add_theme_support' ) ) {
	add_theme_support( 'post-thumbnails' );
	set_post_thumbnail_size( 150, 150, true );
	add_image_size( 'portfolio', 295, 150, true );
	add_image_size( 'twentyfourteen-full-width', 1920, 1269, true );
}

I tried adding this line to my css:

img.attachment-twentyfourteen-full-width {
	width: 1920px;
}

Neither worked. I have run out of ideas. Here is the link:

http://www.patrickahearn.com/houses/31-south-water-street/