I just have spent an hour to detect how to create a windows .ico from an existing image.
This time, I document it:
Prerequisites
Install netpbm, which includes ppmtowinico. and imagemagick which provides convert, i.e.:
apt-get install imagemagick netpbm
Define original file name and wanted icon sizes
PICFILE=foo-bar.png # all formats supported by imagemagick are ok # WinXP supports up to 256, but usually that's a waste of bytes ICONSIZES="64 48 32 16"
Convert and combine.
for S in $ICONSIZES ; do convert -scale ${S}x${S} $PICFILE ${PICFILE}_${S}x${S}.ppm ; done
ppmtowinicon -output ${PICFILE}.ico $(for S in $ICONSIZES ; do echo ${PICFILE}_${S}x${S}.ppm ; done)