1. You will need to have Gimp 2.6 installed and ready.
Now create a new picture with 640 x 480 (480 minus some space for the text cursor). The original Slitaz splash will be 640 x 346 pixels.
2. Now create your image,with your creative works. When done, change the image mode to indexed colors.
IMAGE > MODE > INDEXED
The pre-boot image can only have 16 different colors, minus 2 colors for the text. So, you have to select “Maximum Number Of Color = 14”, reserving 2 colors for the text.
3. Now save the image in PPM format:
FILE -> SAVE AS -> SELECT FILE TYPE (BY EXTENSION) -> PPM IMAGE
Save it (as RAW ppm).
4. Convert the PPM image to LSS image using Syslinux utility ppmtolss16 (a Perl program that comes with the Syslinux package).
# wget http://ftp.nluug.nl/sunsite/system/boot/loaders/syslinux-3.75.tar.gz
# tar xzf syslinux-3.75.tar.gz
Inside the directory syslinux-3.75/utils you can find the “ppmtolss16” Perl script.
Copy the file “ppmtolss16” to where you are working the picture.
# cp syslinux-3.75/utils/ppmtolss16 xxxxxxxx
replace xxxxxxxx with your image location.
# ./ppmtolss16 ‘#ffffff=7’ imagename.lss
Where the ‘#ffffff=7’ is the RGB color of the text cursor (red=ff, green=ff and blue=ff), which is the white color.
Done, you have a .LSS image file.