BMP / RLE format

Helo List !

        I wanted to ask something about BMP files. Im using Photoshop and Gimp to edit / create the .bmp files that i use in my programs. I noticed that all the files i create they usually are about 1.3 MB of size, while some other files that I see on other games (same H-W) are 300 - 400 kb. I wanted to know why mine's are so heavy. The only thing I can see by now, is that the files I create with photoshop are "Win 32 / 24 bit" (but theres no option to make them 16 bit).

May be some one can tell me why mine’s are so heavy, or how to create the same files but with less weight? May be it has something to do with compression?

TIA ! =)

eDU wrote:

Helo List !

        I wanted to ask something about BMP files. Im using 

Photoshop and Gimp to edit / create the .bmp files that i use in my
programs. I noticed that all the files i create they usually are about
1.3 MB of size, while some other files that I see on other games (same
H-W) are 300 - 400 kb. I wanted to know why mine’s are so heavy. The
only thing I can see by now, is that the files I create with photoshop
are “Win 32 / 24 bit” (but theres no option to make them 16 bit).

May be some one can tell me why mine’s are so heavy, or how to create
the same files but with less weight? May be it has something to do
with compression?

TIA ! =)

Eactly, it has to do with compresion. BMP files are not compressed. i.e.
a BMP file has the size: widthheightBpp (Bpp = bits per pixel). For
example, a 640x480 picture in 24bit mode will be 900KB and 1200KB in
32bit mode. If your file contains large “flat zones” (zones with the
same color), you can get a nice reduction by using RLE (Run Length
Encoding), but that’s the only compression you will get in a BMP.
However, you can reduce the size of the file in two ways:

  • Use less bpp, i.e. using only 256colors per image (in Photoshop, go
    to: IMAGE -> MODE -> INDEXED)
  • Use compression: if the image you are storing is a background image,
    and losing a bit of quality does not matter, then save the image as a
    JPG. You will save a lot of space.

I usually use only 256 colors per image (so a 640x480 image is 300KB)
and for the images that don’t need pixel-level-quality (as the
background images, the logos, etc.) I use JPG.

I hope this helps!

  • Use compression: if the image you are storing is a background image,
    and losing a bit of quality does not matter, then save the image as a
    JPG. You will save a lot of space.

Just save the FINAL image on JPEG, do your work on BMP, TIFF or any other
lossless format. If you work on JPEG images and do the usual
(retouch-save-retouch-save…) you are degrading the quality each time you
recompress

I usually use only 256 colors per image (so a 640x480 image is 300KB)
and for the images that don’t need pixel-level-quality (as the
background images, the logos, etc.) I use JPG.

If you use a 75% of quality you don’t loose too much detail.