While it’s a bit of an extreme case, the file for a single 15-page article on Monte Carlo noise in rendering[1] is over 50M (as noise should specifically not be compressed out of the pictures).
I was just checking my PDFs over 30M because of this post and was surprised to see the DALL-E 2 paper is 41.9M for 27 pages. Lots of images, of course, it was just surprising to see it clock in around a group of full textbooks.
If I remember correctly images in PDFs can be stored full res but are then rendered to final size, which more often than not in double column research papers end up being tiny.
[1] https://dl.acm.org/doi/10.1145/3414685.3417881