Re: ZIP BMP (Thanks)

Steve:

You are correct in both counts:


>The amazing compression ratio might be due to a couple of things.  If 
the image has a lot of flat color in it - like a drawing or a logo - or 
areas sharing the same color pattern, then those areas will compress 
down very compactly.  Essentially, the program says, OK, these next 3000 
bytes all have the same value (color), so rather than use 3000 bytes to 
store them, I'll just make note that this next byte should be replicated 
3000 times.

Yes, this image is a border artwork which has a large white area in the 
middle.


>Also, if your image has a color depth of 256 or 64K rather than 16M, 
there are fewer color values for the pixels to have and therefore a 
greater chance that there are areas sharing the same color.

Yes again, this is a lineart image which has less than 16 colors.


Thanks for the assurance that I won't lose quality by zipping a BMP 
file.  Guess I shouldn't complain about the exceptional compression 
ratio anymore.  ;-)

-Collin


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