From This: To This:
Step 1: First things first go to Colors > Auto > White Balance. This isn't always needed, but it definitely does help especially on the image I used. Now duplicate it and set it to Screen 100% Sometimes two Screen layers help, but for this image I only used one. Now Duplicate again and set to Soft Light 100%
Step 2: Merge those layers and then go to Colors > Auto > Color Enhance. After this step you can stop here if your just interested in the coloring, if you'd like to learn how to "stretch" your image or whatever you want to call it then carry on to the next step.
Step 3: This is actual a lot simpler than it looks. Go to the Color Picker Tool and click at the top the image. Over on the Bucket Fill thing it should the color on the Bucket Fill should be similar to the color at the top of your image. Now create a new fill layer and fill it with the color that was at the top of your image and move that layer bellow the image your working with. Now go to Layer > Transparency > Add Alpha Channel and then use your erase tool to erase unwanted things at the top of your image, as for example I erased a tree that was hanging out that I didn't want. Now I moved my image down a little bit. Now your done!!
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