Enforcing image sizing and/or CI sizing action

[mattxwang]

As we've been onboarding people on to the dev team, I've noticed that we've done an ~ eh ~ job of enforcing image sizing/ratio things. I think we should add a quick CI action / script to do this! In particular, images should:

• be ~ around ~ 512px by 512pxslight deviations are fine, but anything over 1000px is not good
• let's shoot for pixel-perfect square aspect ratio!
• the individual filesize should not be larger than 1MB (probably), but ImgBot probably enforces that already
• have a lowercase extension (this is to deal with issues between local development passing and the final build failing); for now, we can just support .png, .jpg, and .jpeg
• stretch goal - autofix situations where the extension needs to be lowercased

I propose that there are two actionables from this ticket:

• a lint-esque action that checks if these properties are true for every image
• a fix-esque npm (or action) that auto-fixes these problems when possible (but let's say a non-square aspect ratio is not fixable)

This ticket is great for slightly more experienced static devs that are interested in CI/CD or want to learn more about software dev best practices!

[mattxwang]

Not super in-tune with the best practice here, but sharp looks cool: https://www.npmjs.com/package/sharp