When I forward an email with attachments in Mac Mail they get huge! Grow by a factor of 15 or 20! For instance, 500 KB of attachments grow to 7 MB.

And i get no indication of the new size until AFTER I send the email, which is too late to prevent clogging the inboxes of recipients.

Anyone know about this problem? Or how to fix it?

I've run various utilities like Disk Warrior, Disk Utility, TTP and ONYX - no change -

Using an eMac G4, 1GHz, 768 MB, plus 120 GB external Firewire drive.

Thanks .......... ted

Hi Ted,

I'm responding to you in the forums rather than privately because someone else may be able to help if I can't. I have read of this sort of problem and it may be related to the type of files that you are attaching. Please tell us the details. Are they PDFs, movies, other things?

so far this has only ocurred with photo image jpgs - at least that's the only type of attachments that have come to my attention as problems -

The same thing happens to me using Entourage and jpegs. I haven't done this yet, but a workaround might be to open the jpeg in Preview, then go to File>Save As and choose gif (or maybe something else that's smaller than a jpeg). At that point, attache the gif to the email and send it.

I'll probably try this sometime but you can let us know if it works for you.

I can't believe you have the same problem in Entourage!
does this indicate that most or all email apps do this?
which would multiply the size of the attachments every time they get emailed by anyone - creating an enormous (and seemingly unnecessary) overload on the net!
this is a more serious issue than i realized!

In a new test I did NOT USE the FORWARD command but ended up with the same problem!!

first i copied ONLY THE FIRST SET of 15 pics and their text totaling about 500KB -
not the second set that came in the original email (which had a total of 1 MB attached)
( Why do so many emails come with a duplicate set of images - is this a related factor? )
then i opened a new email and pasted the 15 jpgs and text into it -
i can't tell how big it was until i send (another big pain)
then i sent it - which took a couple of minutes, even with cable broadband -
then i opened it (from my sent mail box) and saw that it was now 6.2 MB although still only one set of 15! a file growth factor of about x12 as before -

Looking through my sent box i found that one email now had 4 sets of jpgs! Help!

Haven't yet tried your workaround but sounds pretty hard to do with 15 jpgs and interspersed captions for each !

Never, under any circumstances, ever "paste" a JPEG (or any other attachment) into a mail message.

A JPEG file is compressed. When you paste it into an email, you are pasting it uncompressed. That is your problem. Always press the Attach button and find the JPEG file on your disk, or drag the icon for the JPEG file from your disk into your email. If you open the JPEG and then copy/paste it into an email, expect it to balloon to a huge size.

I just made a test and sent a 448 KB jpeg file to myself through Entourage. At the receiving end window, the file showed as 600 KB but when saved on the desktop got back to its exact 448 KB. To make the story more complicated, I checked my e-mail through the web site. There, the same attachment showed as 91 KB. The saved size was 380 KB. The same thing happened when it was forwarded to my Gmail account and downloaded from there. No difference spotted in the images. Looks like there is some additional encoding/compression of these files going on that may alter the size. Or the size calculatrion in different e-mailers may be inaccurate. Can you check what is the size of the sent and downloaded test file? Is it any bigger than the original in the end? The first figures are scary...
Alex
2.3 GHz DP G5, 1GB RAM, OS 10.4.7, Entourage 11.2.6

Nice catch!
However, I could not paste a jpeg file into Entourage. With the paste command only the filename was pasted. Dragging the file into the window showed correct file with correct size. Maybe it is possible to do in Mail? But the poster said something about forwarding.
Alex

Update: did the same thing through Mail.app. Forwarded the message with a jpeg in there to myself and in Mail got the same size as sent. Something may be wrong in the tedsmac's Mail.app
Finally, just pasted a jpeg into an empty message window in Mail. It did paste but the size did not go up - same thing.
Forgot to mention: the file was a Photoshop jpeg file.

jchuzi - tried your workaround but couldn't make a gif in either Preview or CorelPhotoPaint -

one of the problem emails i forwarded was a group of 15 jpgs of major urban skylines around the world with text under each photo - the email was about 500 K and grew to 6.2 M when forwarded and sent -
i downloaded the 15 jpgs to a 'skylines' folder on my desktop - then made the following tests using these jpgs -
test 3 - when i attached just one of the 15 skyline jpgs (60K) to a new email and sent it to myself it remained the same size - (no forwarding here)
test 4 - attached 15 skyline jpgs to new email + sent to myself > no growth
test 5 - Forwarded test 4 > no growth
so the problem only seems to arise when forwarding certain email - which probably had special encoding/compression in it to start with -

tacit - you make a good point about not pasting jpgs. so my "new test" yesterday was flawed, which could account for the jpg growth there.
BUT what about my original question? why do jpgs grow by a factor of 12 to 18 during forwarding and sending (with no pasting involved)?

macnerd10 - i agree that it looks like some additional encoding is going on - but apparently not just in my mac Mail account since jchuzi had the same problem in Entourage - but since you didn't have the problem much if at all with Entourage, it's more complicated -

as to downloading the jpgs to the desktop - it's not important to me what the file size is there, only in an outgoing email - this is what causes headaches with very slow reception and clogging of inboxes -

so, to me, the basic questions remain unanswered -
1. what's the cause?
2. is there some basic way to fix it?

The attachments are being converted to MIME format for transmission and then are decoded back to their original form in the receiving email client. The Wikipedia article the link points to explains why this is necessary in order to transmit non-textual data. The MIME encoded image will, by definition, be substantially larger than the original data image. This is true with all email regardless of what client you are using.