🚀 Feature: Have images fade in only after they've loaded

[JoshuaKGoldberg]

Bug Report Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Overview

Following #215 & #258: I didn't have time to keep in support for fading images after they've loaded. But I'd really like to.

Loading joshuakgoldberg.com on a simulated Slow 3G connection shows the image taking a while then suddenly appearing in:

Screen.Recording.2024-03-12.at.1.44.16.PM.mov

I find this jarring. But even if I didn't find it jarring, I still think it looks cool to have images fade in after the rest of the page. It's a nifty effect.

Additional Info

No response