Now is baby selected. Extract baby (with shortcut ctrl+j):
Create new layer and move this layer under layer with baby. After that select Gradient tool with Radial gradient. Choose the first one preset as is marked with red circle and color you want (in my case light green color). Second color will be white.
Unmark Reverse option. Now click and drag mouse so you will create gradient with white color behind head.
Next step is to select Mixer brush tool. You can use settings like me(in red box). This tool is mixing near colors. So we will retouch skin a bit.








