Смена графики в зависимости от времени года

[Salvage]

Функция:​

 <?php 

function current_season() { 
       $icons = array( 
               "spring" => "images/spring.png", 
               "summer" => "images/summer.png", 
               "autumn" => "images/autumn.png", 
               "winter" => "images/winter.png" 
       ); 

       $day = date("z"); 

       $spring_starts = date("z", strtotime("March 21")); 
       $spring_ends   = date("z", strtotime("June 20")); 

       $summer_starts = date("z", strtotime("June 21")); 
       $summer_ends   = date("z", strtotime("September 22")); 

       $autumn_starts = date("z", strtotime("September 23")); 
       $autumn_ends   = date("z", strtotime("December 20")); 

       if( $day >= $spring_starts && $day <= $spring_ends ) : 
               $season = "spring"; 
       elseif( $day >= $summer_starts && $day <= $summer_ends ) : 
               $season = "summer"; 
       elseif( $day >= $autumn_starts && $day <= $autumn_ends ) : 
               $season = "autumn"; 
       else : 
               $season = "winter"; 
       endif; 

       $image_path = $icons[$season]; 

       echo $image_path; 
} 

?>

Использование:​

<img src="<?php current_season() ?>" alt="" />

От Frapsy:

PHP код:      // 31536000 - секунд в году
// 2592000 - секунд в 30 днях

switch(time() - 31536000 * (date("Y") - 1970)) {
   case 0..2*2592000,11*2592000+1..12*2592000: echo 'картинка зимы'; break;
   case 2592000*2+1..2592000*5: echo 'картинка весны'; break;
   case 2592000*5+1..2592000*8: echo 'картинка лета'; break;
   case 2592000*8+1..2592000*11: echo 'картинка осени'; break;
}