Write a GIMP script to batch-convert a set of icons -- 3

I have a set of PNG icons and I need to batch-convert all of them in bmp/jpg. The project is not to convert images but to give me a working script that I can run using GIMP, to achieve my goals: * convert all files in a folder to bmp/png - bmp: must be 24 bit bmp with grey background instead of transparency; the level of grey should be customizable (or could be a separate background image, to use as default background) - jpg: no special needings For both bmp/jpg, the script must resize the image from 128x128 to 64x64 and save converted images to a different folder. The final bmp images must be usable with the old Borland C++ Builder, that's why they must be 24 bits images and not 32 bits. I show a sample of the original and converted images. I want to run this script from the console, in Windows 10.