Making Fog

Original

Photoshop

Here I will show you how to create fog just by one simple tool of Photoshop: Gradient Tool
Take a look at the original photo, it is easy to see that there are 2 men sitting not in the right places. Therefore, I use Crop Tool to perfect that picture with the 800x600px
In the next step, I choose Gradient tool like this one:













Drag mouse from the top to the middle of the photo, you will see the result
Enjoys