diff --git a/classes/ComicPressMediaHandling.inc b/classes/ComicPressMediaHandling.inc
index 57e95d7..1071585 100644
--- a/classes/ComicPressMediaHandling.inc
+++ b/classes/ComicPressMediaHandling.inc
@@ -1,6 +1,7 @@
 <?php
 
 class ComicPressMediaHandling {
+	var $root_filter    = '%wordpress%/%type-folder%/';
 	var $default_filter = '%wordpress%/%type-folder%/%date-Y-m-d%*.*';
 
 	function _bundle_global_variables() {
@@ -26,7 +27,7 @@ class ComicPressMediaHandling {
 		if (!is_null($filter_to_use)) {
 			if (is_string($filter_to_use)) {
 				if (isset($comic_filename_filters[$filter_to_use])) {
-					return $comic_filename_filters[$filter_to_use];
+					return $this->_convert_to_percent_filter($comic_filename_filters[$filter_to_use]);
 				}
 			}
 		}
@@ -34,7 +35,52 @@ class ComicPressMediaHandling {
 		return $this->default_filter;
 	}
 
-	function get_comic_path($source = 'comic', $override_post = null, $filter = 'default', $multi = false) {
+	function _convert_to_percent_filter($old) {
+		if (strpos(strtolower($old), '%wordpress%') !== 0) {
+			$old = str_replace('{date}', '%date-Y-m-d%', $old);
+			return $this->root_filter . $old;
+		}
+		return $old;
+	}
 
+	function _expand_filter($filter, $type_filter, $override_post = null) {
+		global $post;
+		$this->post_to_use = !is_null($override_post) ? $override_post : $post;
+		$this->type_filter = $type_filter;
+
+		$result = preg_replace_callback('#%([a-z0-9-]+)%#i', array(&$this, '_expand_filter_callback'), $filter);
+		$result = str_replace('.', '\.', $result);
+		$result = str_replace('*', '.*', $result);
+
+		unset($this->post_to_use);
+		unset($this->type_filter);
+
+		return $result;
+	}
+
+	function _abspath() { return ABSPATH; }
+
+	function _expand_filter_callback($matches) {
+		$value = '';
+		switch (strtolower($matches[1])) {
+			case 'wordpress':
+				$value = $this->_abspath();
+				break;
+			case 'type-folder':
+				$value = $this->type_filter;
+				break;
+			default:
+				if (preg_match('#^date-(.*)$#', $matches[1], $date_matches) > 0) {
+					$value = date($date_matches[1], strtotime($this->post_to_use->post_date));
+					break;
+				}
+				$value = $matches[0];
+				break;
+		}
+		return $value;
+	}
+
+	function get_comic_path($type = 'comic', $override_post = null, $filter = 'default', $multi = false) {
+		$filter = $this->get_filter($filter);
 	}
 }
diff --git a/test/ComicPressMediaHandlingTest.php b/test/ComicPressMediaHandlingTest.php
index 603f53e..358c1c5 100644
--- a/test/ComicPressMediaHandlingTest.php
+++ b/test/ComicPressMediaHandlingTest.php
@@ -9,6 +9,10 @@ class ComicPressMediaHandlingTest extends PHPUnit_Framework_TestCase {
 	function setUp() {
 		_reset_wp();
 		$this->cpmh = new ComicPressMediaHandling();
+		$this->default_filter = $this->cpmh->default_filter;
+
+		vfsStreamWrapper::register();
+		vfsStreamWrapper::setRoot(new vfsStreamDirectory('root'));
 	}
 
 	function testBundleGlobalVariables() {
@@ -28,10 +32,12 @@ class ComicPressMediaHandlingTest extends PHPUnit_Framework_TestCase {
 	}
 
 	function providerTestGetFilter() {
+		$cpmh = new ComicPressMediaHandling();
+
 		return array(
-			array(null, '%wordpress%/%type-folder%/%date-Y-m-d%*.*'),
-			array('fail', '%wordpress%/%type-folder%/%date-Y-m-d%*.*'),
-			array(array(), '%wordpress%/%type-folder%/%date-Y-m-d%*.*'),
+			array(null, $cpmh->default_filter),
+			array('fail', $cpmh->default_filter),
+			array(array(), $cpmh->default_filter),
 			array('test', 'test')
 		);
 	}
@@ -44,6 +50,51 @@ class ComicPressMediaHandlingTest extends PHPUnit_Framework_TestCase {
 
 		$comic_filename_filters['test'] = 'test';
 
-		$this->assertEquals($expected_result, $this->cpmh->_get_filter($filter_to_use));
+		$cpmh = $this->getMock('ComicPressMediaHandling', array('_convert_to_percent_filter'));
+		if ($expected_result !== $cpmh->default_filter) {
+			$cpmh->expects($this->once())->method('_convert_to_percent_filter')->with($expected_result)->will($this->returnValue($expected_result));
+		} else {
+			$cpmh->expects($this->never())->method('_convert_to_percent_filter');
+		}
+
+		$this->assertEquals($expected_result, $cpmh->_get_filter($filter_to_use));
+	}
+
+	function providerTestConvertToPercentFilter() {
+		return array(
+			array('', '%wordpress%/%type-folder%/'),
+			array('{date}', '%wordpress%/%type-folder%/%date-Y-m-d%'),
+			array('%wordpress%/%type-folder%/{date}', '%wordpress%/%type-folder%/{date}'),
+		);
+	}
+
+	/**
+	 * @dataProvider providerTestConvertToPercentFilter
+	 */
+	function testConvertToPercentFilter($old_filter, $new_filter) {
+		$this->assertEquals($new_filter, $this->cpmh->_convert_to_percent_filter($old_filter));
+	}
+
+	function providerTestExpandFilter() {
+		return array(
+			array('', ''),
+			array('%test%', '%test%'),
+			array('%wordpress%', vfsStream::url('root')),
+			array('%wordpress%%wordpress%', vfsStream::url('root') . vfsStream::url('root')),
+			array('%test test%', '%test test%'),
+			array('%wordpress%/%type-folder%', vfsStream::url('root') . '/comic'),
+			array('%date-Y%', '2009'),
+			array('%wordpress%/%type-folder%/%date-Y-m-d%*.*', vfsStream::url('root') . '/comic/2009-01-01.*\..*'),
+		);
+	}
+
+	/**
+	 * @dataProvider providerTestExpandFilter
+	 */
+	function testExpandFilter($filter, $expected_result) {
+		$cpmh = $this->getMock('ComicPressMediaHandling', array('_abspath'));
+		$cpmh->expects($this->any())->method('_abspath')->will($this->returnValue(vfsStream::url('root')));
+
+		$this->assertEquals($expected_result, $cpmh->_expand_filter($filter, 'comic', (object)array('ID' => 1, 'post_date' => '2009-01-01 15:00:00')));
 	}
 }