#687

add ".png" check

models/user.go

@@ -955,6 +955,9 @@ func isUsableName(names, patterns []string, name string) error {
 		if name == names[i] {
 			return ErrNameReserved{name}
 		}
+		if strings.HasSuffix(name, ".png") {
+			return ErrNameReserved{name}
+		}
 	}
 
 	for _, pat := range patterns {