Re: OE attachments grow in file size

From: Michael Santovec (michael_santovec_at_prodigy.net)
Date: 11/20/04 

Date: Sat, 20 Nov 2004 14:25:10 -0800

What sizes are you looking at? If you are looking at the attachment size, that may be
reporting the original file size and not the encoded size. I have seen some
inconsistencies in OE where it reports the attachment file size.

But the message size has to grow compared to the attached file. In the case of a simple
text file, where quoted-printable encoding is used, the overhead can be as little as 3%.
For other file types, the overheard is typically around 40%.

For some additional information, see:
Decoding Internet Attachments - A Tutorial
http://pages.prodigy.net/michael_santovec/decode.htm 

-- 
Mike - http://pages.prodigy.net/michael_santovec/techhelp.htm
"Steve" <nr4p@NOJUNKearthlink.net> wrote in message 
news:ugKnd.6900$pK6.2425@newsread2.news.atl.earthlink.net...
>I appreciate that you spent alot of time on your response. Rest assured the files are 
>going to someone else typically a family member who has requested it and has high speed.
>
> But I have tried the same thing on my corporate email (Outlook with MS Exchange server) 
> and the files do not grow with this magnitude.
>
> -- 
> Steve
> "Vanguard" <no_email> wrote in message news:OZlLrExzEHA.2656@TK2MSFTNGP14.phx.gbl...
>> "Steve" <nr4p@NOJUNKearthlink.net> wrote in message 
>> news:6aInd.6685$pK6.4809@newsread2.news.atl.earthlink.net...
>>> Whenever I try to take a large file such as a jpegs, zip, or mpeg of about 7-8mb, OE6 
>>> reports it as a 12mb file (looking at it in the attachment line). Then my mail service 
>>> won't take it since its over 10mb. But it definitely is smaller in the Pre-attached 
>>> state on my HD.
>>>
>>> OE6 (XP Home sp2), seems to grow attachments by about 40-50%.
>>> This does not happen with Outlook on my busness account.
>>>
>>> Searched MS and googled and haven't seen this. Any ideas why OE6 does this? How to 
>>> stop it?
>>> thanks
>>>
>>>
>>
>>
>> Whether it is Outlook Express, Outlook, Thunderbird, Pegasus, or whatever e-mail client 
>> of choice, attachments will ALWAYS be larger when attached to an e-mail then their size 
>> in the file system.  Where do you think the file gets "attached"?  There is no separate 
>> file floating around and following your e-mail.  The file is WITHIN the body of your 
>> e-mail message as a specially encoded plain-text section.  That means your file gets 
>> converted from its binary version to a plain-text version (which takes more bytes).
>>
>> If you look at the raw message format of your sent message (i.e., copy yourself to you 
>> get a copy, but which requires you look at it with OE since Outlook bastardizes the 
>> content of received e-mails into Microsoft's proprietary format which is NOT the actual 
>> content that got received), you'll see the section showing the encoded version of the 
>> file you "attached".  Now use a hex editor to go look at the content of the file on 
>> your hard drive (that you attached).  Notice that the contents are NOT the same: one is 
>> binary and the other (in the e-mail) is the converted plain-text version of that binary 
>> file.  If you attached a text file, the encoded MIME part will look very similar but 
>> include additional formatting info.  If you attach a binary file, like a JPEG, the 
>> encoded MIME part containing the definition of the "attached" file will look very 
>> different than what you would see in a hex editor. Expect about a 33% average increase 
>> in the size of the attached file in your e-mail due to the conversion.  For example, in 
>> a test case, sending myself a 2-line message with a 23.8KB JPEG file "attached" to it 
>> resulted in a received e-mail message that was 38KB in size (a 60% increase in size). 
>> The text encoding includes compression but the less compressible is a then the larger 
>> it will be in its converted form within the e-mail, and if it is already a compressed 
>> file then it might actually inflate more (JPEGs are compressed files).  As another 
>> example, a 4.29KB .txt file will enlarge a test e-mail to 10KB, whereas a 2.18KB .zip 
>> file with that contains that same .txt file will result in an e-mail message that is 
>> 8KB in size.  So you reduced the file to 50% of its size by compressing it but you only 
>> gained a 20% for the size of the e-mail (i.e., encoding to plain text with compression 
>> an already compressed file will actually inflate the size of your e-mail message).
>>
>> If you are using UUencode to encode your attached file (an old method) then go Google 
>> on UUencode/UUdecode to see how encoding works for attaching files using that scheme. 
>> It is likely, however, that you are using MIME to separate the parts of your message. 
>> One MIME part will contain your message and another MIME part will contain the 
>> text-encoded version of your attached file.  You can search http://www.rfc-editor.org/ 
>> to find the RFCs that describe MIME and read how it encodes attachments.
>>
>> The enlargement of the attached file along with throttling of mail servers to provide 
>> response to all connected users (so one user doesn't usurp all bandwidth with a huge 
>> message download) along with old servers not handling some content correctly makes 
>> e-mail a stupid choice for transferring files.  E-mail is not designed nor should be 
>> used as a replacement for FTP (file transfer protocol).  If you have a huge file to 
>> send someone, do you really want to be rude by consuming up a lot of their disk quota 
>> for their e-mail account and make them waste time to download your huge message which 
>> they may not want or they only want your message without your picture which might be 
>> superfluous to your message?  Remember that there is still a huge number of user using 
>> dial-up.  Save your file on a server somewhere, like on your personal web pages or 
>> other online storage, and include a link to it in your message.  Then the recipient can 
>> quickly download your small message and THEY can decide if they want to also download 
>> your file.
>>
>> -- 
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