diff --git a/phpBB/includes/functions_posting.php b/phpBB/includes/functions_posting.php
index 5e25648eb8..6a53213230 100644
--- a/phpBB/includes/functions_posting.php
+++ b/phpBB/includes/functions_posting.php
@@ -564,26 +564,27 @@ function get_supported_image_types($type = false)
 			switch ($type)
 			{
 				// GIF
-				case 1:
+				case IMAGETYPE_GIF:
 					$new_type = ($format & IMG_GIF) ? IMG_GIF : false;
 				break;
 
 				// JPG, JPC, JP2
-				case 2:
-				case 9:
-				case 10:
-				case 11:
-				case 12:
+				case IMAGETYPE_JPEG:
+				case IMAGETYPE_JPC:
+				case IMAGETYPE_JPEG2000:
+				case IMAGETYPE_JP2:
+				case IMAGETYPE_JPX:
+				case IMAGETYPE_JB2:
 					$new_type = ($format & IMG_JPG) ? IMG_JPG : false;
 				break;
 
 				// PNG
-				case 3:
+				case IMAGETYPE_PNG:
 					$new_type = ($format & IMG_PNG) ? IMG_PNG : false;
 				break;
 
 				// WBMP
-				case 15:
+				case IMAGETYPE_WBMP:
 					$new_type = ($format & IMG_WBMP) ? IMG_WBMP : false;
 				break;
 			}
diff --git a/phpBB/includes/functions_upload.php b/phpBB/includes/functions_upload.php
index fbf57026e4..983ccdfc82 100644
--- a/phpBB/includes/functions_upload.php
+++ b/phpBB/includes/functions_upload.php
@@ -989,22 +989,22 @@ class fileupload
 	function image_types()
 	{
 		return array(
-			1 => array('gif'),
-			2 => array('jpg', 'jpeg'),
-			3 => array('png'),
-			4 => array('swf'),
-			5 => array('psd'),
-			6 => array('bmp'),
-			7 => array('tif', 'tiff'),
-			8 => array('tif', 'tiff'),
-			9 => array('jpg', 'jpeg'),
-			10 => array('jpg', 'jpeg'),
-			11 => array('jpg', 'jpeg'),
-			12 => array('jpg', 'jpeg'),
-			13 => array('swc'),
-			14 => array('iff'),
-			15 => array('wbmp'),
-			16 => array('xbm'),
+			IMAGETYPE_GIF		=> array('gif'),
+			IMAGETYPE_JPEG		=> array('jpg', 'jpeg'),
+			IMAGETYPE_PNG		=> array('png'),
+			IMAGETYPE_SWF		=> array('swf'),
+			IMAGETYPE_PSD		=> array('psd'),
+			IMAGETYPE_BMP		=> array('bmp'),
+			IMAGETYPE_TIFF_II	=> array('tif', 'tiff'),
+			IMAGETYPE_TIFF_MM	=> array('tif', 'tiff'),
+			IMAGETYPE_JPC		=> array('jpg', 'jpeg'),
+			IMAGETYPE_JP2		=> array('jpg', 'jpeg'),
+			IMAGETYPE_JPX		=> array('jpg', 'jpeg'),
+			IMAGETYPE_JB2		=> array('jpg', 'jpeg'),
+			IMAGETYPE_SWC		=> array('swc'),
+			IMAGETYPE_IFF		=> array('iff'),
+			IMAGETYPE_WBMP		=> array('wbmp'),
+			IMAGETYPE_XBM		=> array('xbm'),
 		);
 	}
 }