Support for multiple sizes in a single theme?

[veltman]

Right now if you wanted to generate Facebook/Twitter (1280x720) and Instagram (640x640) audiograms, you'd have to define two separate themes with two separate background images and generate the audiogram twice. It would be nice if you could generate an audiogram once and get back a whole family of videos, one for each site.

Not sure how this would work given that logo placement and that sort of thing would change at different sizes. It would require spec'ing out and constraining a lot of the visual options to make it work across sizes. May or may not be desirable.