adding class featured image on posts

Hi there,

I would like to add a customized class to the featured images to blog pages through the elements module.

I'm deciding against the header module because I want to have more control over the wrappers and the ability to do things like reposition the title relative to the banner for mobile devices.

Based on an earlier support request, I adapted the below code to add the style-svg class to the image (this is to have it work with support-svg plugin). I notice this doesn't work with the posts header. Is there a way to modify it so that it does? Please let me know. Thank you in advance.

add_filter( 'generate_featured_image_output', function( $output ) {
    return sprintf( // WPCS: XSS ok.
        '<div class="post-image CUSTOM-CLASS">
					<a href="%1$s">
						%2$s
					</a>
				</div>',
				esc_url( get_permalink() ),
				get_the_post_thumbnail(
					get_the_ID(),
					apply_filters( 'generate_page_header_default_size', 'full' ),
					array(
						'itemprop' => 'image',
                                                 'class'=> 'style-svg'
             )
         )
    );
} );