So most images in wikis have descriptions, like here:
But you can not only add text to the descriptions, but also tables. To do that, click on Visual editing, then on the image description, then on the plus sign add the top, then on "Table", then reduce the amount of columns to two, and you have a template prototype. it won't be perfect, but it will be something.
It’s kind of wonky and doesn’t look as good as the normal template. Also, the normal template uses the same exact parameters and is much easier to use, making it much harder to mess something up every time.
It would also be difficult to change all of pages if the user template was eventually carried over to the MSMG wiki, with user pages thenceforth being susceptible to discontinuity (with some using the template and others using the table).
So I think I should just keep trying to find a way to add the template to the MSMG wiki.