Hi Samantha,
Thank you for reaching out to us. It’s due to Wordpress image sizing, the original image is converted to many sizes and the plugin or theme can call that image with a specific size. Though, if you like to switch to original, please add this code to your child theme’s functions.php file:
if ( ! function_exists( 'x_featured_image' ) ) :
function x_featured_image( $cropped = '' ) {
$stack = x_get_stack();
$fullwidth = ( in_array( 'x-full-width-active', get_body_class() ) ) ? true : false;
if ( has_post_thumbnail() ) {
if ( $cropped == 'cropped' ) {
if ( $fullwidth ) {
$thumb = get_the_post_thumbnail( NULL, 'full', NULL );
} else {
$thumb = get_the_post_thumbnail( NULL, 'full', NULL );
}
} else {
if ( $fullwidth ) {
$thumb = get_the_post_thumbnail( NULL, 'full', NULL );
} else {
$thumb = get_the_post_thumbnail( NULL, 'full', NULL );
}
}
switch ( is_singular() ) {
case true:
printf( '<div class="entry-thumb">%s</div>', $thumb );
break;
case false:
printf( '<a href="%1$s" class="entry-thumb" title="%2$s">%3$s</a>',
esc_url( get_permalink() ),
esc_attr( sprintf( __( 'Permalink to: "%s"', '__x__' ), the_title_attribute( 'echo=0' ) ) ),
$thumb
);
break;
}
}
}
endif;
The recommended resolution of images depends upon the maximum width of your site, e.g if it’s set to 1200px then it’s best that you upload the image that has the width of 1200px so it doesn’t look blurry or pixelated.
For more information, you can check out the codex:
https://developer.wordpress.org/reference/functions/add_image_size/
https://codex.wordpress.org/Function_Reference/remove_image_size
To improve the load time and performance, please checkout https://theme.co/apex/forum/t/customizations-performance/210
Hope this helps!