2 files changed, 2 insertions, 2 deletions
diff --git a/USAGE b/USAGE
index 3fea3fa..bd48ed8 100644
--- a/USAGE
+++ b/USAGE
@@ -54,7 +54,7 @@ Running
 			example: --name Example
 
 		--id-charset CHARSET
-			sets the charset for file IDs in URLs to CHARSET; should only include URL-safe characters and no slashes
+			sets the charset for file IDs in URLs to CHARSET; should only include URL-safe characters and no slashes or underscores
 			example: --id-charset 0123456789
 
 		--id-length LENGTH
diff --git a/storage.go b/storage.go
index 7c674fc..f33dc34 100644
--- a/storage.go
+++ b/storage.go
@@ -153,7 +153,7 @@ func (s *Storage) randomId() string {
 }
 
 func (s *Storage) idToFolder(subfolder, id string) string {
-	for len(id) < 4 {
+	for len(id) < 3 {
 		id = "_" + id
 	}
 	return path.Join(s.Folder, subfolder, id[0:1], id[1:3], id)