If your images appear to be low-quality or grainy (despite being high-quality when uploaded), this may be because of image compression plugins or features being enabled on your hosting server. You may need to get in touch with your hosting provider to see about disabling such features.
Typically, these plugins or services will serve compressed versions of your images depending on device width. If you are using Wordpress Jetpack, you will need to ensure image optimization features are turned off.
Wordpress 5.3
With the introduction of Wordpress 5.3, large images that exceed 2560px in dimension will automatically be compressed.
To disable this Wordpress core feature, you can create a child version of Semplice and add a line of code to your Semplice 'functions.php' file:
add_filter( 'big_image_size_threshold', '__return_false' );You can it right after the 'misc functions' line of code:
// -----------------------------------------
// misc functions
// -----------------------------------------