Genesis: Stop archives from using first attached image as fallback when no featured image is set.

functions.php

<?php

// Don't include the above.

add_filter( 'genesis_get_image_default_args', 'prefix_stop_auto_featured_image' );
/**
 * Stop Genesis archives from using first attached image as fallback when no featured image is set.
 *
 * @param  array $args Default image arguments.
 *
 * @return array       Amended default image arguments.
 */
function prefix_stop_auto_featured_image( $args ) {
	if ( ! isset( $args['context'] ) || 'archive' !== $args['context'] )
		return $args;
	$args['fallback'] = false;
	return $args;
}

Hey Gary, thank you for this! I modified this code to let me set a default fallback image of my choosing: https://gist.github.com/oncecoupled/1fa7de6b15e862a94b1f

I'm noticing that where my theme does a modified post image and uses genesis_get_image(), the attr and size are not being read in properly for my fallback image, only for my manually set featured images.

<?php
function modified_do_post_image() {
    if ( in_array( 'genesis-grid', get_post_class() ) ) {
        if ( ! is_singular() && genesis_get_option( 'content_archive_thumbnail' ) ) {
        $img = genesis_get_image( array(
            'format'  => 'html',
            'size'    => 'half-feature',
            'context' => 'archive',
            'attr'    => genesis_parse_attr( 'post-image' ),
        ) );

        if ( ! empty( $img ) )
            printf( '<a href="%s" title="%s">%s</a>', get_permalink(), the_title_attribute( 'echo=0' ), $img );
        }
    }
}

Is there something I'm missing that would make this work for both the set and fallback featured images, or is it not easily accomplished at this time?

Best,
Lauren