Is it possible for a PDF file to increase in size when it is emailed?

by on September 3, 2010

Q: Using yahoo mail and windows 7 ultimate I sent an email with an attached pdf file to a friend . My PDF’s size was 370 KB.

My friend insists that the PDF he received was almost 10 times larger (being 3.51 MB)! He is on windows 7 Live Mail (Microsoft). I could not believe that and I told him that he obviously makes a mistake.

So, for evidence, we both provided each other with jpg captures showing the different sizes!

Then, for testing purposes I sent the same PDF to another email address (G Mail) and they confirmed that the size of the file received there was the same with that of my outgoing file (370KB),

I cannot understand how this can be done. If I am to believe the first recipient then we have to accept that an outgoing file might possibly be increased in size as much as ten times before reaching a recipient!

Is that at all possible?

3 Responses to “Is it possible for a PDF file to increase in size when it is emailed?”

    That strikes me as pretty strange. Have him forward the e-mail he got back to you and compare the attachments. Maybe do a few more tests of sending stuff to him and have him forward it back again to see if the files are being altered in transport or if it is just his e-mail client displaying information wrong.

    PS – This is probably just a minor bug somewhere and not a sign that some Hollywood Villain is intercepting your PDF files and then altering them.


    Thanks for the reply. I have already requested his forwarding my mail back.


    Your suggestion was useful.
    He replied that he has deleted the mail and file in question.
    Therefore, we have to say “no file, no issue”.
    Sorry for bothering and thank you.