WP: Plugin function to return image in specified size (if any), default otherwise.

wpc_get_logo_with_size.php

<?php
/**
 * Get Logo.
 *
 * Returns logo of WPCouple.com in specified width (if any).
 * 
 * @param array $atts Array of attributes.
 * @return mixed
 */
function wpc_get_logo( $atts ) {
	// Get argument values.
	$arguments = shortcode_atts( array( 'size' => null ), $atts );
	
	// Size is set.
	if ( ! empty( $arguments['size'] ) ) {
		// Set source & size of image in img tag.
		$logo = '<img width="' . $arguments['size'] . 'px" src="' . plugins_url( 'images/wp-couple-logo.png', __FILE__ ) . '">';
	} else { // Size is not set.
		// Set source of image tag.
		$logo = '<img src="' . plugins_url( 'images/wp-couple-logo.png', __FILE__ ) . '">';
	}
	
	// Return logo.
	return $logo;
}