Hi there, I’ve done a bit more digging around on this to try and see what could be causing the resizing of your images. Try the following.

In the functions.php, find the code below, around line 115 and edit the value for the width in the add_image_size( ‘slider’, 1020, 9999 ); to a higher px width. Then reupload your large images as a new slide.

//custom media image sizes
if ( function_exists( ‘add_image_size’ ) ) {
add_theme_support( ‘post-thumbnails’ );
add_image_size( ‘menucard_thumb’, 9999, 100 );
add_image_size( ‘gallery_thumb’, 260, 9999 );
add_image_size( ‘mediumwidth’, 588, 9999 );
add_image_size( ‘fullwidth’, 906, 9999 );
add_image_size( ‘slider’, 2000, 9999 );
}