For comparison:

War and Peace is only 3.2 MB, or 3.9 MB with the overhead of HTML

source: https://www.gutenberg.org/ebooks/2600

Yeah but the manga version is 6.6GB

Okay, now I'm curious, link to the manga version?

This manga is part of the variety art works series which transcribes (transdraws?) important literary works for younger japanese who might not have the understanding yet to read them in their orig. translation.

You can find a list of series here: https://myanimelist.net/people/21441/Variety_Art_Works

Edit: This is the same series that includes mein kampf and capital, both which have had many panels screenshotted you can find around the net circulating (f.e. if you'we ever met a mangaised Marx, or some weird collection of nazi's illustrated they are quite common tropes)

I just made that up for the joke

How does a professional web designer even put up a picture that large without going through some basic compression?

I've personally experienced this at work before.

A non-technical person uploaded the image to the CMS, assuming it will be scaled down at some point after uploading. A web developer used the image from the CMS, assuming it was scaled down at some point before being exposed for the frontend to access it. In reality the image never got scaled down anywhere, and ended up on the frontend in its full 9 MB glory. This ended up happening with several images.

I (not a frontend dev) ended up finding it because I was writing a strongly-worded message to my team lead about the huge pile of unnecessary tracking/surveillance scripts being forced on frontend users, and I wanted to make the point that it was making the frontend slow and heavy. It turned out out that the tracking scripts were nothing compared to the huge images!

Apparently nobody else bothered to check this before me, and/or didn't stop for half a second to think about it when they saw "Total page size: 13 MB" in their browser devtools, and/or didn't actually attempt to do any investigation when they saw our shitty Lighthouse rating. The world is full of professionals in name and status, but not in attitude.

I am a one man shop running a news site and put my site through webpagetest every Monday morning. I find it crazy that big companies apparently don’t do this.

You're likely more dedicated than most. There is a certain level of ignorance that allows these people to continue in comfort and unfortunately its not fixable because they don't know and likely don't care.

I am generally surprised when a web developer produces anything at all without 200 separate requests on every pageload and a 20M+ footprint.

Which in turn, the margin AWS has on the bandwidth they sell must be insane! People seem to pay for "premium" bandwidth and not even batting an eye, people just swallow that stuff right up. Just like TE, it must make them a ton of money.