I continued to expand on the original batch file and I feel I have an awesome working setup that allows me to create multiple retro forwarders at once. it resizes images and strips the meta from jpgs. only condition is that input image must be square jpgs.
There are two things that need to be place in the build folder ( prod.keys ) file and mogrify.exe. This is found in the imageMagick downloads(search it in google) select the portable version I used ImageMagick-7.0.11-11-portable-Q16-x64.zip. just copy "mogrify.exe" in the build folder.
Now go to the main folder in the edit and run file open it with a notepad application i used notepad++ code looks nice and easy to organize. read the comments. the title ID is optional if it's not included it generates a random id for you. problem is if you are unlucky it might generate a title id that matches one of your installed titles. to avoid this I included a file with titleids of games and choose a title that I'll never play or install on the switch and copy its title id (the first 16 digits).
There is this issue that I found that building NROs might be not be 100% right. like theme installer forwarder gives an error. if you build the forwarder from scratch(editing the main.c latest nx-loader and compiling it) that problem gets resolved. but It just too much work and I don't want to get too involve on this project.
Attached is my current set up. just drop the images in build/images(square jpgs) and edit and run the batch script. just copy the line above and replace with your info. read the comments on the file. the output will have the app name so you know which NSP is which.
if you are going to be adding and building a forwarder at a time then add the word "rem" in the begining of the line and will get ignored next run. or recreate them by deleting inside the nsp folder.
I found this way more useful as i created 8 nsps in a matter of seconds. and i can recreate them just as easy if I ever need to change the image or update any of the source files, or rename the roms directory. I don't even have to open cmd.lol so this way if nintendo breaks them again as long as there is a working exefs files with the latest files for retro roms they can be recreated.
This is why I'm wondering what edits
@mpham could have made to the main.c file or know where he got it so they can be remade in the future.
edit: I had a bit more time, and I think i got it. I created an unified exefs that works for retro forwarders and nro forwarders based on the latest hbl-loader. it works on all of my tests so far. Let me know how it works for you.
HAVE FUN!