Is there a way to re-disable coloured emoji support on newer versions of FF on Linux?

I know that late last year, Firefox 50 added a feature to natively display emoji in colour on Linux. Previously (if you were on a website without its own implementation) they displayed as black and white outlines, or just nothing.

Is there a way to go back to how it was? Maybe I'm just a grumpy person, but the sight of emoji almost always irritates me, and I think I'd prefer them to stay visible but inconspicuous.