$_img = Mage::getBaseUrl('media') . $s['image'];
$_imgsize = getimagesize($_img);

$image = imagecreatefromjpeg(Mage::getBaseDir('media') . $s['image']);
$width = imagesx(image);
$height = imagesy(image);

$_imgsize = getimagesize(Mage::getBaseDir('media') . DS . $s['image']);

$path = Mage::getBaseDir('media') ... ;
$image = new Varien_Image($path);
$x = $image->getOriginalWidth();
$y = $image->getOriginalHeight();