Change default Image Folder

[Algernon]

is there a way to change the default iso image folder with a script?

https://www.ventoy.net/en/plugin_control.html you can specify which folder to check for isos/img in to increase speeds for long lists and exclude looking in other folders without using a .ventoyignore files by adding global control plugin option lines to your ventoy.json like follows, just change "/ISO" to any other folder on part 1. I named mine "Catalog". 
{
    "control": [
        { "VTOY_DEFAULT_SEARCH_ROOT": "/ISO" },
    ]
}

I have seen it mentioned that some would like to boot from iso not on the usb device but instead from a computers folder but not sure if it was ever accomplished. Maybe another global control plugin can be added in the future such as "VTOY_DEFAULT_SEARCH_LOCAL_ROOT" with another starting prefix like true / or current one expanded somehow to allow specifiying a folder like /sda7/manjaro/Desktop/ventoyisofolder?