Save individual render layers to image files with this new add-on by Tamir Lousky.
This script was written so that anyone could easily render out all the render passes on all render layers into separate files, to composite in any program they would like to use (e.g. GIMP / Photoshop / Nuke / AE).
One of the concept / texture artists I work with asked for a quick way to do this, as he repeatedly had to save to individual images manually through the image editor, or to manually create and connect the renderlayer node's pass outputs into file output node/s in the compositor, both repetitive time consuming tasks.
The add-on automatically creates a file output node for each render pass on each render layer, so when you render, it will save the respective image files in the specified render output folder.
Here's a video demonstrating how the add-on works and its usage:
For further details about installation, usage, the script's development process and other stuff, you welcome to visit my blog.
To download the script, go to the github repository.