How to specify image dimensions?

is this what you mean? found it in an older support topic. it adds a size attribute to the generated html.

In the plugin’s functions.php file, you can change line 132 (as of version 0.9.9.6) to the following:

$html .= '<img class="' . esc_attr( $args['thumb_align'] ) . ' rpwe-thumb" src="' . esc_url( $image ) . '" alt="' . esc_attr( get_the_title() ) . '" width="' . $args['thumb_width'].'" height="'. $args['thumb_height'] .'">';