Working With Bitmap Layers

Adjust Brightness and Contrast

If you're into photography you'll know the source file we're working with is pretty bad. That's why we got rid of the sky... there wasn't much we could do to improve it!

Now that it's out of the picture, we can make some adjustments to help the hills pop a little bit. Select the image, then Filters > Adjust Colors > Brightness/Contrast

You'll want to increase the contrast:

This is what the hills looked like before:

...and after: