Re: maintain the size of an image file (jpeg)

From: Murray (forums_at_HAHAgreat-web-sights.com)
Date: 01/28/05 

Date: Fri, 28 Jan 2005 07:09:35 -0500

Hmm - *saving* an image, in and of itself, does nothing to reduce the weight
of it. Adjusting the parameters with which it is saved (like the quality in
a JPG, or the number of colors in a GIF) are what affect the final weight of
the image, since you are removing pixels (effectively) when you do that. I
assumed that after the resize, you would have then exported/saved the image
at the MINIMUM acceptible quality already. In this case, opening and saving
again would not be expected to have any beneficial effect, and may in fact
degrade things beyond that minimum acceptability level.

One of the worst things you can do to a JPG image, by the way, is to JPG it
again, so to speak. 

-- 
Murray
"Tom J" <tomj_ga@despammed.com> wrote in message 
news:35tqk8F4og823U1@individual.net...
>
> "Murray" <forums@HAHAgreat-web-sights.com> wrote in message 
> news:eWdYduLBFHA.2428@TK2MSFTNGP14.phx.gbl...
>> OK - so let's go with that.  What format are the images saved in?  I will 
>> assume JPG for purposes of argument.
>>
>> On a 1024x768 screen, and assuming 96ppi (pixels per inch), an 8.5x11 
>> image is 8.5*96 pixels wide by 11*96 pixels wide.  Altogether that would 
>> be 816pixels X 1056 pixels or 861,700 pixels square roughly.  That's 
>> pretty big assuming 1 byte per pixel.  The JPG compression is not too 
>> bad - let's assume 90% of the image can be compressed.  Even so, each 
>> image is 86K. That's big.  In addition it's bigger than some screens you 
>> are likely to have visiting your site, which is awkward.
>>
>> Here's what I think you ought to do.  Open each image in a graphics 
>> editing program and resize it to - say - 600 wide by whatever height. 
>> That should be your largest image.  When you put it on the web page, make 
>> sure that you leave it at that size - in other words, do not resize the 
>> image in the browser.
>>
>> Does that make sense?
>>
>> -- 
>> Murray
>
> Just to add to what you just said, after resizing, load the image into 
> Paint and save. That will reduce the weight of it by about 1/2.  Just 
> finished doing a bunch.
>
> Tom J
>
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