Go to my first entry and follow the tutorial. Just don't put the clouds and floras in the background. Remaining is same.when you will reach to the final image.Use Fuzzy select tool on the image and drag it to get a selection just like the image below.
step 2 of 4
now press delete button which will delete most of the figure from image and result like the figure below.
step 3 of 4
now create a transparent layer and put it below the first layer than fill it with black color which will produce results like this.
step 4 of 4
Now take the eraser tool and delete all the green elements from the image carefully and save the final image.