diff --git a/pkg/mime/mime.go b/pkg/mime/mime.go
index 24e2a752671..fa48a2bdea0 100644
--- a/pkg/mime/mime.go
+++ b/pkg/mime/mime.go
@@ -38,7 +38,7 @@ func init() {
 // a mime type with the given extension.
 // TODO(labkode): check that we do not override mime type mappings?
 func RegisterMime(ext, mime string) {
-	mimes.Store(ext, mime)
+	mimes.Store(strings.TrimPrefix(ext, "."), mime)
 }
 
 // Detect returns the mimetype associated with the given filename.