The python script is very simple.
I used my scene with Mickey Mouse (my boy like this funny cartoon).
This is the python script.
import bpy
bpy.context.scene.render.use_border = False
bpy.context.scene.render.use_crop_to_border = False
bpy.ops.render.render()
R="Render Result"
bpy.data.images[R].save_render("/home/your_username/test_render.png")
See the output image:
The next source code it's used for border and crop.
Only if you want to use it.
bpy.context.scene.render.use_border = False
bpy.context.scene.render.use_crop_to_border = False
Also you can use this to set resolution percentage.
For example if you want to render just 10% of resolution use this:
bpy.context.scene.render.resolution_percentage =10