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;
 			}