You can also ask for a single map tile of any location at any size.

REST Query to get a tile
http://local.yahooapis.com/MapsService/V1/mapImage?appid=rlerdorf&location=94539
Returned XML
<Result>
http://img.maps.yahoo.com/mapimage?MAPDATA=NE6uked6wXUvMKeeO65.zg9FRNGF36TLiC8QU14ROsDkbVumowh8Jm3JSJUKwebcVHHXcvWDLt8WExnWh59FAevHEV5ynmh6WyJ3zNdmrLJYh3S95w--
</Result>
Example
<html><head><title>Map Tile Demo</title>
<script type="text/javascript">
<?php
function request_cache($url$dest_file$timeout=43200) {
  if(!
file_exists($dest_file) || filemtime($dest_file) < (time()-$timeout)) {
    
$stream fopen($url,'r');
    
$tmpf tempnam('/tmp','YWS');
    
file_put_contents($tmpf$stream);
    
fclose($stream);
    
rename($tmpf$dest_file);
  }
}

$cities = array("San Francisco""Los Angeles""Seattle""Atlanta""Chicago""Dallas",
                
"Vancouver, Canada""New York City""Toronto""Miami, FL""Boston");

$width 600$height 300$zoom 7;
 
$url  "http://local.yahooapis.com/MapsService/V1/mapImage?appid=rlerdorf"
$url .= "&image_height=$height&image_width=$width&zoom=$zoom";
$url .= "&location=";
$i=0;
foreach(
$cities as $city) {
  
$q $url.rawurlencode($city); 
  
$tmp '/tmp/yws_tile_'.md5($q); 
  
request_cache($q$tmp);
  
$xml simplexml_load_file($tmp); 
  if(
$i==0$first = (string)$xml;
  echo <<<EOB
image$i = new Image();
image
$i.src = "$xml";
EOB;
  
$i++;
}
?>
</script>
</head><body>
<?php
echo <<<EOB
<div id="img_container" 
  style="float:left; height:
{$height}px; width:{$width}px; padding: 0px 10px 0px 10px;">
<img id="the_img" src="
$first" height="$height" width="$width"/></div>
EOB;
$i=0;
foreach(
$cities as $city) {
  
$q rawurlencode($city);
  echo <<<EOB
<a href="http://maps.yahoo.com/beta/index.php?#trf=0&q1=$q"
   onmouseover="document.getElementById('the_img').src=image
$i.src;
                this.style.backgroundColor='white';"
   onmouseout="this.style.backgroundColor='#eeee33';">
$city</a><br />
EOB;
  
$i++;
}
?>
</body></html>
Output
Map Tile Demo
San Francisco
Los Angeles
Seattle
Atlanta
Chicago
Dallas
Vancouver, Canada
New York City
Toronto
Miami, FL
Boston