The preview is 530x300px on a 1920x1080 screen vs the image shown being 336x188px
How this passed any sort of QA is beyond me
What on the YouTube home page could possibly require 12MB of JS alone? Assuming 60 characters per line, that’s 200k lines of code? Obviously ballpark and LoC != complexity, but that seems absurd to me.
The code is minified so there's relatively few characters for each source line, if you run it through a pretty-printer to restore sensible formatting then it turns into well over half a million lines of code.