Get category thumbnail image magento
Just try to use below code :
<?php echo Mage::getBaseUrl('media').'catalog/category/'.Mage::getModel('catalog/category')->load($_category->getId())->getThumbnail(); ?>
Example :
<img class="img-responsive" src="<?php echo Mage::getBaseUrl('media').'catalog/category/'.Mage::getModel('catalog/category')->load($_category->getId())->getThumbnail(); ?>" />
