i didnt made this, someone else did and their website is gone (the PDF file is the copy of the website). I don't know how to cracked the program to modify it. Args files are custom made to only run on Arcade Game Studio unless someone with more technical knowledge finds a way to program args files just like someone once did with gameboy files or Xbox versions.
16:9 is new that wasn't part of the retro experience so the original developer never added it. There is no way to add pictures on the sides but you can put the game in window mode and add a picture in the background or something.