Image saved as PDF is larger than image saved as JPG

[jay fresno]

Can anyone tell me why the same image saved as a PDF is larger in file size than that same image saved as JPG?

Does Acrobat have some extra settings or baggage that it adds?

[Bernd Alheit · Accepted solution]

A PDF file contains more then the image data.

[jay fresno]

That's what I suspected. Can you elaborate on that as to what other things the PDF contains or is there a web page that explains what it contains.

[try67 · Accepted solution]

There's a 1000+ page technical document that explains all of it, if you're interested...

But seriously, that's an extremely complicated issue. Suffice it to say that a PDF will contain metadata information, page information, images information, text streams information, fonts information, color space information, printing information, fields/comments/links/bookmarks information, etc., etc. While not all of that is necessarily present in your specific file, it can be, so a PDF with an image will almost always be larger than just the image itself, unless it was down-sampled while creating it, in which case it could be smaller (but the image will have a lower quality).

[jay fresno]

Thank you for your helpful explanation, try67. It is enough information for me to get an understanding of why the PDF is larger.