E Book ( PDF’s )

Hi can anyone help, I have come across a PDF, Murach’s HTML5 And CSS3 on two different sites and decided to download both of them, one was a torrent, when they had downloaded I checked them and found one to be 170mb and the other to be 252mb. I have checked both copy’s and they appear to be the same but obviously they are not.
the only thing I can think of it there has been some loss say in the graphics of the 170mb version or other info has been added to the 252mb copy. Either way this is a big file for a PDF on HTML5 and CSS3, most of the other two hundred or so E books on coding languages that I have average about 30mb.
Answer #1
Well, PDFs support multiple levels of compression, So maybe they’re just compressed
differently! It might also be graphics related (A bunch of BMP images would take more space than JPEG’s for example) As for the 30MB average, Each case to it’s own as they say!
The size varies according to length, images and compression.
Answer #2
Well, PDFs support multiple levels of compression, So maybe they're just compressed
differently! It might also be graphics related (A bunch of BMP images would take more space than JPEG's for example) As for the 30MB average, Each case to it's own as they say!
The size varies according to length, images and compression.
Yea I just checked the graphics on both books and the 170mb version was ~love~ in comparison to the other.
I’ve kept the good one and deleted the other.
Answer #3
I’d guess it in the compression of any jpgs embedded in the pdf.
I’ve seen some 2 Mb jpg become 600 mb when re-saved at 80% quality, with no noticable image quality loss.
If it has only ten jpgs in it, that’s 15 mb saved there..