the### [at] hotmailcom (The Mad Hatter) wrote in 
<web.3d680ad7a0dd952795946e520@news.povray.org>:

>  Rightclicking and viewing properties gives a different image filesize than
>viewing from the OS Console.
>
>Now I understand a differece in rounding up, or chiping off digits, but
>sometimes
>the values are off by quite an amount.  And viewing the image in an image
>manipulators gives me yet another different value.  Every app calculates an
>image filesize different.  Is there a true method to this? I would image so.
>
>Once entering the irtc I was afraid I was over the max K limit of my image.
>3/4 applications said I was under, and the other said I was over the limit.
>I am curious as to how the irtc calculates the size of images as well now.
>
>I vote that this kind of system should be standardized!
>
>
>

It it standardized, you just need to know which one to follow :). There are a 
few elements at play, so you pick;

The Megabyte can be expressed as 1 million bytes or 1,048,576 (2^10) bytes.

Your real size difference will show when opening a compressed image format like 
PNG, GIF or JPG in a graphics application. The app must decompress the image 
into a more raw bitmap format in order to manipulate it and display it on the 
screen. 

When you ask the graphics app how large the file is, it will simply calculate 
bit depth per pixel * pixels wide * pixels high of the raw bitmap as displayed 
on the screen, and cached in memory. This size could be as much as 10 times the 
size of the file when it is stored on your harddrive or being electronically 
transferred.

I have a PNG file opened in Paint Shop Pro right now. PSP reports the filesize 
as 1.4 MegaBytes. Checking this file's properties from MS-Windows, Explorer 
says '205KB (209,926 bytes)' -- you see Microsoft decided to report both the 
2^10 bytes and the Million byte values.

I think IRTC is asking for the 2^10 flavor, in my example that would be the 
205KB

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