...or use most classes of non-destructive adjustment layers. Or use many of the more desirable and time-saving (read: cost-effective, even when compared to "free as in beer" plugins. Gimp isn't useless by any means, but it's not a Photoshop replacement yet, any more than Corel's Paint Shop Pro is. (But it will be soon, right? It's been "going to be" for a very long time.)