Hi,
GIMP has many uses like painting, photography, animation and etc.
In my view a person develop a particular interest in it's usage, the term workflow will refer to it. Workflow start with GIMP's preference and is in part a group thing followed by a personal part.
One consequence is that, after the development of a workflow, the actual menu become inadequate for this routine.

Attach here is plug-ins of my work on that, called 'workflow_setup'. There was previous work on it (example: at http://www.gimp.org/tutorials/Automate_Editing_in_GIMP/ by Stephen Kiel) but more complex.
This plug-in should be working for Linux and Windows, but with surely some missing pieces and finish.
It's based on the idea of RUN_INTERACTIVE action like the one explained by 'MareroQ' in this forum, coupled with workflow and interactivity.
It's not wholly an automatic plug-in but needs your workflow knowledge and experimentation to set-up effectively. So not for beginner, since for example: there are many variations in actions which complicate things.

The menu location is '<Image>/Extensions/Workflow setup' of the two plug-ins: "->workflow manager..." and "Workflow menu...".
They are included in the file 'workflow_setup.py'. You set-up your 'action' workflows with first "->workflow manager..." then close that and launch them with "Workflow menu...".

"->workflow manager...", begins with some hypothetical action workflows that you can use as partial info and template for yours.
The action line is central for this plug-in, it starts with a '[' and ends with a ']', has three parts separate by a comma: action, blurb (the blurb in the template is from Linux) and working_state.
The 'PDB actions' list represents what's available for this plug-in at the time you launch "->workflow manager...". All are line number followed by an action line but not all will work for you or the plug-in "Workflow menu...".
Under 'Workflow actions' a line that end with ':' is a tag or if it begin with a '[' an action line like the PDB action. You can edit the tag line but keep the ':' ending. You can edit the action line whole or in parts: for blurb piecemeal and for working_state don't touch the first character 'number-'; except if your familiar with the action then number > 2.
Naturally you can add whole tag line or from the PDB side copy an action line, minus the line number. You can save 'Workflow actions' and actualize by clicking on the box: 'Workflow actions'.

If in the bottom line of GIMP the "Waiting for workflow_manager..." message disappears with no 'workflow_manager' window appearing; this is a problem that you should report here.

"Workflow menu...", opens the workflow file save in "->workflow manager..." and tries directing the launch of your actions.
Some of the action return value(s), see end of the blurb that appears as tool-tip (for version > 0.1.1), these values should appear in the 'Error console'.
A working_state less than '3-...' is used for automatic testing of an action, while if the user start it with '3- ' (for version > 0.1.2) it stop the plug-in for an image-action; state greater than 3 it's only for a short comment not touch by "Workflow menu...".
In version 0.1.3 the 'exec. type' multiple development is introduced while 'tutorial' will not be considered further. It's most useful for case with few tested actions completing each others.

Edit4: version in attachment is now 0.1.2 with 'gimpplugin' registration. Corrected a bug in workflow_manager (November 02, 2015).
Edit5: revision of the above text and version in attachment is now 0.1.3
Edit6: same version in attachment less two bugs (January 19, 2016).

I had to give the plugin permission to run. I am a bit confused as to it's purpose but it seems to run gmic ok.

Wallace: you're welcome, but don't use 'folder' in "Workflow menu...".

Kimba:

Conclude that you are on Linux (first sentence), sorry for the omission.
If you have no personal workflow it have few purpose other than applying an action to all the image open, if many, in GIMP. If you have workflow, start with plug-in "->workflow manager..." (waiting a bit to appear) choose in the PDB to adapt it to your own , left-click on button 'Workflow actions' for verification, if OK click on button 'save workflow' and quit. Load the pertinent images in GIMP and start plug-in "Workflow menu..." apply actions one after the other ... You can start many plug-in "Workflow menu...", if you want actions from many workflows accessible!

Graechan:

I don't know why.

What does the plug in do exactly?

oh, okay.

With the first "workflow_setup.py" you could select 'folder' instead of GIMP, see the screen capture in the attachment. Today after the edit, in the new "workflow_setup.py" you couldn't, only GIMP is active.
The 'folder' one need more work.

Alright, thanks for clarifying that.

A few initial observations from tinkering with the workflow_setup plug-in.

1. The Workflow Manager appears takes over your Gimp session (note the bottom of the canvas window), until you restart Gimp.
2. This might be wrong but; the only way I found to remove a procedure from your Workflow actions list is to overwrite it's blank space in the list. For example if it's the first item, backspace to make the second item first or if it's the last item backspace to overwrite the line it was formerly on. Use the Workflow actions button to verify.
3. This is fairly obvious but do not include line numbers from the PDF actions list in your Workflow actions list.
4. If you need a better look at the PDB actions list, search 'actions_all.lst' in a text editor.

and/or search Gimp Procedure browser to find the proper name sequence for an action.

Here's an example of 3 items I've added for fun.



I've left the original 'testing' and 'examples' in place, these procedures can be removed. I'm guessing the script will regenerate examples it the Workflow actions list is blank? Only playing with it briefly that's my experience so far, maybe rob_brz1 can comment?