okay, so this one is really hacked together. theoretically there is a way to have it simply download a video in one go, but I ran out of time to try to get that working. this will absolutely spam you with downloads as the images get converted. you will probably get a notification that this page is trying to "download" multiple files. just accept that. they will be numbered.

if you want an automated way to convert the folder of images just go here and read this top answer.