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Old Dec 8, 2007, 8:30 AM   #1
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Images that are downsized for email attachment lose image quality on the receiving end. How canI restore the original image size and quality?
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Old Dec 8, 2007, 9:20 AM   #2
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Short Answer:

You can't.

Long answer:

There are two methods to downsizing: 1. Reduce the resolution, & 2. Increase the compression. Most often these two methods are used simultaneously.

When you reduce the resolution of an image, you are discarding detail. An image captured by a 6MP image sensor (3000x2000) can be reduced to a 1.5MP image (1500x1000) only by averaging the pixels in the original image to determine the value of a single pixel in the new image. Once the average is calculated and stored, there is no way to determinethe values of the original pixels.

JPEG is a compressed image format. In fact, there are no JPEG images that haven't had some amount of compression applied. (An uncompressed image is a RAW image. If you are not familiar with RAW, you can find many discussions in these forums about RAW.) The compression used in JPEG images is not a lossless compression. You may be familiar with the compressed file format called ZIP. ZIP is a lossless compression format, which ensures that the original information can be recovered by uncompressing the file or files later. JPEG uses a form of compression that does not permit the recovery of the original information.

Downsizing discards information that can not be restored.
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Old Dec 8, 2007, 5:23 PM   #3
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Thank you. Then, is it possible to send high quality images via email?


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Old Dec 8, 2007, 5:37 PM   #4
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Yes, of course it is. The only limit will be the size limit of attachments with either your or your sender's ISP. But today, those sizes are pretty generous.
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Old Dec 8, 2007, 10:02 PM   #5
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Sometimes your ISP will place limits on the size of the attachments you can send, and sometimes, the recipient's ISP will place limits on the size of attachements they can receive.

If you send a message that has ten 3MB files attached, someone will undoubtedly object, and the recipient will not receive the message. But if you send ten messages, each of which has a 3MB file attached, they will probably all get through.
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Old Dec 9, 2007, 4:33 AM   #6
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u can also send files via yahoo messenger or msn messenger

these go direct so no mail server problems

Gary
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Old Dec 9, 2007, 9:15 AM   #7
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If you are going to send large attachements, or many medium sized ones, you should know if that is acceptable to the recipient. Speaking as one with a dial-up connection, I get upset with large attachments.

Also, if you are going to be sending those to several people, I think it is much better to put them up in the form of a web page and e-mail the link.
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Old Dec 9, 2007, 3:45 PM   #8
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I always check my email account on the web before I download it. This lets me check for spam and virii as well as large attachments. Some people haven't gotten the idea that I don't care to receive video files and such.

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