Reducing bmp size.

[Kurt_]

I am re-flashing my bios. It has the capability to display a custom image instead of diagnostics. The catch is that it has to be a 16 colour, 640 x 480 bitmap that is under 10kb.

I can't get it under 140kb. I downloaded some software to reduce the size, and it doubled the size. I honestly don't feel like I can reduce it any more.

Any ideas?

Here's the log.

Code: Select all

Prepare v2.04  05/27/98    
(c) Phoenix Technologies Ltd.

SCRIPT FILE: logo.scr
EXECUTION TIMESTAMP: Wed Sep 16 17:59:22 2009


PREPARE/CATENATE Command Parser Ver 2.0  3/11/98
Parsing: 'logo.scr'

     Line:  5  COMPRESS  LZINT			
     Line: 10  LOGO LOGO.BMP -F:10             


PREPARE/CATENATE Command Parser END

Global Compression Mode = LZINT
ERROR: compressed module size for LOGO.MOD > specified ROM footprint

[marshallh]

I think most of them use some kind of LZW compression, which depends on the source image being simple and with few colors.

A simple company logo, yes. A photo isn't going to work at all. Mind posting the source image?

[Kurt_]

I'm working with two possibilities, whichever turns out better. The goal is to add some hilarity to a stolen laptop.

[gamemasterAS]

I used to have fbi boot screen and log-in screens.

[Grandmasterjimmy]

Lowest I can get is 25kb.

[Kurt_]

HOW do you get it smaller? Every bitmap I save is 140kb

[Grandmasterjimmy]

Photoshop, index color, save as 4 bit bitmap.

[Kurt_]

I don't use photoshop.

[marshallh]

You can do that in MSPaint too, BTW. Save As > 16-color

[bacteria]

I got same results; on BMP got 140k, when tried software to reduce size came in at 282k.

Got it 12.2k on jpeg though.

[robm]

I got 32.4Kb, still working on it though.

Edit: Seems that's the lowest I can get it Sorry. That's at 4-bit grayscale. I can get it tiny if you're cool with no color information at all.
Edit2: 28.3, with color.

[Kurt_]

A friend of mine explained bitmap compression to me. Reducing the image size did it, the DEA one came out on top for looking the most official.

[marshallh]

I was gonna say, since circle area increases exponentially with diameter, making it a bit smaller frees up a lot of pixels