Hi,
im a mac user and i suggest you to read
https://www.mobileread.com/forums/showthread.php?t=14340
If the case is to convert pdf with images, i use the GREATEST ONE
https://www.mobileread.com/forums/showthread.php?t=12790
this way i convert all pdf to images with a software i downloaded from mobileread (i dont remember name) and with the manga program it converts all double page image to single page image and make a new pdf