i’ve been getting quite a few pdfs from annas archive that have lots of photographs that look all filled with jpg artifacts or something. most of these i think were originally uploaded to the internet archive. is there any way to correct this or am i stuck between not reading the book or having to read it looking like this?
They have lots of jpg artefacts because they are heavily compressed jpgs. Nothing you can do about it except finding the uncompressed original, which would have a much larger filesize.
As far as I recall all pixel images in PDFs are jpgs. So they will all have varying degrees of artefacts.