It's only about twice the statutory damages. And it looks like the article is only using $25,000 per work for that number. For willful infringement, statutory damages can go up to $150,000, which would be about $2.8 billion for 18,755 photos here. I'd say she's being fairly generous by offering to settle for a mere $1 billion!
I would have sued them for the full amount the law permitted for each image if the company goes under as a result that would act as example/discouragement for any other company that would think about doing that in the future.
People get fined ridiculous amounts all the time as discouragement so why shouldn't companies have the same happen to them their technically a person in the US no?
If the company goes under because it can't make the full payment, I'd accept a transfer of the remaining copyrights and promptly place everything in the public domain.