Added timestamps to pictures to stop caching

store/store.go

@@ -77,6 +77,7 @@ type PostStore interface {
 type UserStore interface {
 	Save(user *model.User) StoreChannel
 	Update(user *model.User, allowRoleUpdate bool) StoreChannel
+	UpdateUpdateAt(userId string) StoreChannel
 	UpdateLastPingAt(userId string, time int64) StoreChannel
 	UpdateLastActivityAt(userId string, time int64) StoreChannel
 	UpdateUserAndSessionActivity(userId string, sessionId string, time int64) StoreChannel