As mentioned the LaTex images are embedded and hosted elsewhere. One example
URL of such a formula image is:

<https://d2nchlq0f2u6vy.cloudfront.net/15/09/28/2ef343b32c126111c6ded35c9262f4a7/f5a08e6720a99b394fd0d2dbfca4f9c0/lateximg.png?tcb=1599074030>

Maybe you need to add something like that to the scan rules:

+*.cloudfront.net/*

and perhaps this:

+www.slader.com/textbook/9781337624183-calculus-9th-edition/*

however, I am not sure about it.