Picasa

Before After

If you look at the left one, you can see something like stain. So I tried to erase it using retouch tool of Picasa. It might still look a little bit unnatural but obviouly the stain has gone! Picasa is an amazing FREE software and good for beginners like me. First I was thinking about using Photoshop but it has too many tools and that kind of stuff and I don't think I can handle it. But Picasa on the other hand is very easy to use:)