Create Custom Social Images for Building Pages

[vkoves]

If we want to make Electrify Chicago easy to share, adding a helpful social preview image (maybe showing the building image, the energy mix, and some rankings) would be helpful. Here's how it looks right now:

For comparison, here's how GitHub's social images look when you share this repo:

I did something like this with imagemagick for chiwho.bike, where I created a template image and then added the interview photo on top of it, but adding text or graphs is likely to be more complex.