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[OM] Re: file compression

Subject: [OM] Re: file compression
From: Mark Marr-Lyon <markml@xxxxxxx>
Date: Mon, 21 Jun 2004 11:58:49 -0600
Zip is a lossless compression algorithm so you won't lose anything, but at best 
it'll compress about as well as TIFF/LZW.  It may even do worse, since I think 
TIFF compresses the color channels separately but I don't remember for sure.  
However, zipping an image file will only help if the image is previously 
uncompressed.  Zipping a compressed TIFF will result in a file that is probably 
about the same size or a little larger than the TIFF, while zipping a JPEG will 
most likely result in a file that is quite a bit larger than the original JPEG. 
 If you need to send a JPEG image to someone on a phone connection, either 
reduce the number of pixels in the image, or increase the amount of compression 
when you save it, then just send the jpeg file as an attachment without further 
zipping.

Mark

On Monday, June 21, 2004, at 10:26AM, Gregg Iverson <golftooter@xxxxxxxxxxxx> 
wrote:
>My question concerned the sending of large jpg files over a phone 
>connection.  I am also concerned that the receiving ISP might deny an email 
>that contains a large attachment.  What does a zipped photo lose when it is 
>opened?
>
>Discussions of TIFF, JPG etc. have been covered.  I don't remember anything 
>about  zipped files.
>
>gregg


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