Hello,

I am a new gimp user. I would like to do some batch job of image manipulation.
I now it is possible through scripting and command line execution. For example I have two images and want to do following steps:
1. Open 1st image
2. Open 2nd image and add as a layer to the 1st image
3. Resize 2nd and move to (x,y) position
4. Save result as 3rd image.

Then in the script should be included proper procedures (e.g. gimp-file-load,gimp-image-get-active-layer). How I now which procedures should I use and what is going 'under the hood' of gimp.

Is there a possibility to preview, look up what procedures gimp uses when I edit picture manually?
This is something like GimpScripter or --verbose mode but for procedures.

Checkout, BIMP: Batch Image Manipulation Plugin and review The Procedure Browser for some ideas.
Help → Procedure Browser

In the python-fu or script-fu console, you can hit the "browse" button do have access to a list of all functions.

This said, ImageMagick's "composite" utility may be a much better tool for this.