I am using excerpts where I have added images.
in order to get your plugin working properly I have made following changes, where I have put the output into a table:
function yoast_rss_shortcode( $atts ) {
extract(shortcode_atts(array(
"feed" => '',
"num" => '5',
"excerpt" => true
), $atts));
require_once(ABSPATH.WPINC.'/rss.php');
if ( $feed != "" && $rss = fetch_rss( $feed ) ) {
$content = '<table width="100%" border="0">';
if ( $num !== -1 ) {
$rss->items = array_slice( $rss->items, 0, $num );
}
foreach ( (array) $rss->items as $item ) {
$content .= '<tr><td><p><a href="'.esc_url( $item['link'] ).'">'. $item['title'] .'</a></p>';
if ( $excerpt != false && $excerpt != "false")
{
$content .= '<p><span class="rss_excerpt">'. $item['summary'] .'</span></p></td></tr>';
}
}
}
$content .= '</table>';
return $content;
}