diff --git a/trac/conf/trac.ini b/trac/conf/trac.ini
index cbb7ae6..166ea6f 100644
--- a/trac/conf/trac.ini
+++ b/trac/conf/trac.ini
@@ -53,7 +53,7 @@ roadmap = disabled
 [mimeviewer]
 enscript_modes = text/x-dylan:dylan:4
 enscript_path = enscript
-max_preview_size = 2621440
+max_preview_size = 262144
 mime_map = text/x-dylan:dylan,text/x-idl:ice,text/x-ada:ads:adb
 php_path = php
 silvercity_modes =